161 research outputs found
Extracting double-quantum coherence in two-dimensional electronic spectroscopy under pump-probe geometry
Two-dimensional electronic spectroscopy (2DES) can be implemented with
different geometries, e.g., BOXCARS, collinear and pump-probe geometries. The
pump-probe geometry has its advantage of overlapping only two beams and
reducing phase cycling steps. However, its applications are typically limited
to observe the dynamics with single-quantum coherence and population, leaving
the challenge to measure the dynamics of the double-quantum (2Q) coherence,
which reflects the many-body interactions. We propose an experimental technique
in 2DES under pump-probe geometry with a designed pulse sequence and the signal
processing method to extract 2Q coherence. In the designed pulse sequence with
the probe pulse arriving earlier than pump pulses, our measured signal includes
the 2Q signal as well as the zero-quantum (0Q) signal. With phase cycling and
the data processing using causality enforcement, we extract the 2Q signal. The
proposal is demonstrated with the rubidium atoms. And we observe the collective
resonances of two-body dipole-dipole interactions of both and
lines.Comment: 7 pages, 5 figure
Oriented Object Detection in Optical Remote Sensing Images using Deep Learning: A Survey
Oriented object detection is one of the most fundamental and challenging
tasks in remote sensing, aiming at locating the oriented objects of numerous
predefined object categories. Recently, deep learning based methods have
achieved remarkable performance in detecting oriented objects in optical remote
sensing imagery. However, a thorough review of the literature in remote sensing
has not yet emerged. Therefore, we give a comprehensive survey of recent
advances and cover many aspects of oriented object detection, including problem
definition, commonly used datasets, evaluation protocols, detection frameworks,
oriented object representations, and feature representations. Besides, the
state-of-the-art methods are analyzed and discussed. We finally discuss future
research directions to put forward some useful research guidance. We believe
that this survey shall be valuable to researchers across academia and industr
A multinode quantum network over a metropolitan area
Towards realizing the future quantum internet, a pivotal milestone entails
the transition from two-node proof-of-principle experiments conducted in
laboratories to comprehensive, multi-node setups on large scales. Here, we
report on the debut implementation of a multi-node entanglement-based quantum
network over a metropolitan area. We equipped three quantum nodes with atomic
quantum memories and their telecom interfaces, and combined them into a
scalable phase-stabilized architecture through a server node. We demonstrated
heralded entanglement generation between two quantum nodes situated 12.5 km
apart, and the storage of entanglement exceeding the round-trip communication
time. We also showed the concurrent entanglement generation on three links. Our
work provides a metropolitan-scale testbed for the evaluation and exploration
of multi-node quantum network protocols and starts a new stage of quantum
internet research.Comment: 21 pages in total, 4 figures and 1 table in the main text, 5 figures
and 8 tables in the supplementary materia
Olmutinib (BI1482694/HM61713), a Novel Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor, Reverses ABCG2-Mediated Multidrug Resistance in Cancer Cells
The main characteristic of tumor cell resistance is multidrug resistance (MDR). MDR is the principle cause of the decline in clinical efficacy of chemotherapeutic drugs. There are several mechanisms that could cause MDR. Among these, one of the most important mechanisms underlying MDR is the overexpression of adenosine triphosphate (ATP)-binding cassette (ABC) super-family of transporters, which effectively pump out cytotoxic agents and targeted anticancer drugs across the cell membrane. In recent years, studies found that ABC transporters and tyrosine kinase inhibitors (TKIs) interact with each other. TKIs may behave as substrates or inhibitors depending on the expression of specific pumps, drug concentration, their affinity for the transporters and types of co-administered agents. Therefore, we performed in vitro experiments to observe whether olmutinib could reverse MDR in cancer cells overexpressing ABCB1, ABCG2, or ABCC1 transporters. The results showed that olmutinib at 3 μM significantly reversed drug resistance mediated by ABCG2, but not by ABCB1 and ABCC1, by antagonizing the drug efflux function in ABCG2-overexpressing cells. In addition, olmutinib at reversal concentration affected neither the protein expression level nor the localization of ABCG2. The results observed from the accumulation/efflux study of olmutinib showed that olmutinib reversed ABCG2-mediated MDR with an increasing intracellular drug accumulation due to inhibited drug efflux. We also had consistent results with the ATPase assay that olmutinib stimulated ATPase activity of ABCG2 up to 3.5-fold. Additionally, the molecular interaction between olmutinib and ABCG2 was identified by docking simulation. Olmutinib not only interacts directly with ABCG2 but also works as a competitive inhibitor of the transport protein. In conclusion, olmutinib could reverse ABCG2-mediated MDR. The reversal effect of olmutinib on ABCG2-mediated MDR cells is not due to ABCG2 expression or intracellular localization, but rather related to its interaction with ABCG2 protein resulting in drug efflux inhibition and ATPase stimulation
Dirac semimetal PdTe2 temperature-dependent quasiparticle dynamics and electron-phonon coupling
Dirac semimetal PdTe2 single-crystal temperature-dependent ultrafast carrier
and phonon dynamics were studied using ultrafast optical pump-probe
spectroscopy. Two distinct carrier and coherent phonons relaxation processes
were identified in the 5 K - 300 K range. Quantitative analysis revealed a fast
relaxation process ({\tau}_f) occurring on a subpicosecond time scale which
originated from electron-phonon thermalization. This was followed by a slower
relaxation process ({\tau}_s) with a time scale of ~ 7-9.5 ps which originated
from phonon-assisted electron-hole recombination. Two significant vibrational
modes resolved at all measured temperatures and corresponded to Te atoms
in-plane (E_g), and out-of-plane (A_1g), motion. As temperature increased both
phonon modes softened markedly. A_1g mode frequency monotonically decreased as
temperature increased. Its damping rate remained virtually unchanged. As
expected, E_g decreased uniformly as temperatures rose. At temperatures above
80 K, there was insignificant change. Test results suggested that pure
dephasing played an important role in the relaxation processes. PdTe2 phonon is
thought responsible for its superconductive properties. Examining phonons
behavior should improve the understanding of its complex superconductivity.Comment: 6 pages, 4 figure
Metabolomic Analysis Uncovers Energy Supply Disturbance as an Underlying Mechanism of the Development of Alcohol‐Associated Liver Cirrhosis
Alcohol-associated liver disease (ALD) is caused by alcohol metabolism's effects on the liver. The underlying mechanisms from a metabolic view in the development of alcohol-associated liver cirrhosis (ALC) are still elusive. We performed an untargeted serum metabolomic analysis in 14 controls, 16 patients with ALD without cirrhosis (NC), 27 patients with compensated cirrhosis, and 79 patients with decompensated ALC. We identified two metabolic fingerprints associated with ALC development (38 metabolites) and those associated with hepatic decompensation (64 metabolites) in ALC. The cirrhosis-associated fingerprint (eigenmetabolite) showed a better capability to differentiate ALC from NC than the aspartate aminotransferase-to-platelet ratio index score. The eigenmetabolite associated with hepatic decompensation showed an increasing trend during the disease progression and was positively correlated with the Model for End-Stage Liver Disease score. These metabolic fingerprints belong to the metabolites in lipid metabolism, amino acid pathway, and intermediary metabolites in the tricarboxylic acid cycle. Conclusion: The metabolomic fingerprints suggest the disturbance of the metabolites associated with cellular energy supply as an underlying mechanism in the development and progression of alcoholic cirrhosis
Arterial Embolization Hyperthermia Using As2O3 Nanoparticles in VX2 Carcinoma–Induced Liver Tumors
BACKGROUND: Combination therapy for arterial embolization hyperthermia (AEH) with arsenic trioxide (As(2)O(3)) nanoparticles (ATONs) is a novel treatment for solid malignancies. This study was performed to evaluate the feasibility and therapeutic effect of AEH with As(2)O(3) nanoparticles in a rabbit liver cancer model. The protocol was approved by our institutional animal use committee. METHODOLOGY/PRINCIPAL FINDINGS: In total, 60 VX(2) liver-tumor-bearing rabbits were randomly assigned to five groups (n = 12/group) and received AEH with ATONs (Group 1), hepatic arterial embolization with ATONs (Group 2), lipiodol (Group 3), or saline (Group 4), on day 14 after tumor implantation. Twelve rabbits that received AEH with ATONs were prepared for temperature measurements, and were defined as Group 5. Computed tomography was used to measure the tumors' longest dimension, and evaluation was performed according to the Response Evaluation Criteria in Solid Tumors. Hepatic toxicity, tumor necrosis rate, vascular endothelial growth factor level, and microvessel density were determined. Survival rates were measured using the Kaplan-Meier method. The therapeutic temperature (42.5°C) was obtained in Group 5. Hepatotoxicity reactions occurred but were transient in all groups. Tumor growth was delayed and survival was prolonged in Group 1 (treated with AEH and ATONs). Plasma and tumor vascular endothelial growth factor and microvessel density were significantly inhibited in Group 1, while tumor necrosis rates were markedly enhanced compared with those in the control groups. CONCLUSIONS: ATON-based AEH is a safe and effective treatment that can be targeted at liver tumors using the dual effects of hyperthermia and chemotherapy. This therapy can delay tumor growth and noticeably inhibit tumor angiogenesis
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