Optical clocks are emerging as next-generation timekeeping devices with technological and scientific use cases. Simplified atomic sources such as vapor cells may offer a straightforward path to field use, but suffer from long-term frequency drifts and environmental sensitivities. Here, we measure a laboratory optical clock based on warm rubidium atoms and find low levels of drift on the month-long timescale. We observe and quantify helium contamination inside the glass vapor cell by gradually removing the helium via a vacuum apparatus. We quantify a drift rate of 4×10-15/day, a 10 day Allan deviation less than 5×10-15, and an absolute frequency of the Rb-87 two-photon clock transition of 385,284,566,371,190(1970) Hz. These results support the premise that optical vapor cell clocks will be able to meet future technology needs in navigation and communications as sensors of time and frequency.
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http://dx.doi.org/10.3390/s22051982 | DOI Listing |
Front Pharmacol
December 2024
Department of Radiology, Tianjin Key Laboratory of Functional Imaging and Tianjin Institute of Radiology, Tianjin Medical University General Hospital, Tianjin, China.
Introduction: Although photodynamic therapy (PDT) shows considerable potential for cancer treatment due to its precise spatial control and reduced toxicity, effectively eliminating residual cells under hypoxic conditions remains challenging because of the resistance conferred by these cells.
Methods: Herein, we synthesize an amphiphilic PEGylated polyphosphoester and present a nanocarrier (NP) specifically designed for the codelivery of hydrophobic photosensitizer (chlorin e6, Ce6) and hypoxia-activated prodrugs (tirapazamine, TPZ). We investigate the antitumor effect of NP on both cellular and animal level.
Int J Nanomedicine
December 2024
State Key Laboratory of Ophthalmology, Optometry and Visual Science, National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, People's Republic of China.
Background: Developing carrier-free nanomedicines via self-assembly of two antitumor drug molecules is a potential strategy for enhancing the combination treatment of tumors. Similarly, conventional chemotherapy combined with photodynamic therapy may synergistically improve the antitumor effect while minimizing the adverse reactions associated with antitumor treatment. Hyaluronic acid (HA) can bind to overexpressed HA receptors on the tumor cell surface, increasing cell internalization and resulting in good tumor-targeting properties.
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January 2025
School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000, Thailand.
In this work, we synthesize a quinoline-based heptamethine cyanine, QuCy7, with sulfonate groups to enhance water solubility. This dye demonstrates exceptional near-infrared absorption beyond 750 nm, accompanied by photothermal properties but low photostability. Encapsulating QyCy7 with polyethylene glycol to form nanopolymer, QuCy7@mPEG NPs, addresses the issue of its photoinstability.
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January 2025
BK21 Program, Department of Applied Life Science, Konkuk University, Chungju 27478, Republic of Korea.
The tumor-specific efficacy of the most current anticancer therapeutic agents, including antibody-drug conjugates (ADCs), oligonucleotides, and photosensitizers, is constrained by limitations such as poor cell penetration and low drug delivery. In this study, we addressed these challenges by developing, a positively charged, amphiphilic Chlorin e6 (Ce6)-conjugated, cell-penetrating anti-PD-L1 peptide nanomedicine (CPPD1) with enhanced cell and tissue permeability. The CPPD1 molecule, a bioconjugate of a hydrophobic photosensitizer and strongly positively charged programmed cell death-ligand 1 (PD-L1) binding cell-penetrating peptide (CPP), is capable of self-assembling into nanoparticles with an average size of 199 nm in aqueous solution without the need for any carriers.
View Article and Find Full Text PDFMater Today Bio
February 2025
Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
Combining photothermal and chemotherapy using single nanoplatform is an emerging direction in cancer nanomedicine. Herein, a magnetic field (MF) induced combination of chemo/photothermal therapy is demonstrated using FeO@mSiO@Au core@shell@satellites nanoparticles (NPs) loaded with chemotherapeutic drug doxorubicin (DOX), both and An application of an external MF to the NPs dispersion causes magnetophoretic movement and aggregation of the NPs. While the synthesized NPs only slightly absorb light at ∼800 nm, their aggregation results in a significant near infrared (NIR) absorption associated with plasmon resonance coupling between the Au satellites in the NPs aggregates.
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