89 research outputs found
Plasmonic nano-resonator enhanced one-photon luminescence from single gold nanorods
Strong Stokes and anti-Stokes one-photon luminescence from single gold
nanorods is measured in experiments. It is found that the intensity and
polarization of the Stokes and anti-Stokes emissions are in strong correlation.
Our experimental observation discovered a coherent process in light emission
from single gold nanorods. We present a theoretical mode, based on the concept
of cavity resonance, for consistently understanding both Stokes and anti-Stokes
photoluminescence. Our theory is in good agreement of all our measurements.Comment: 14 pages, 7 figures, 2 table
CiT-Net: Convolutional Neural Networks Hand in Hand with Vision Transformers for Medical Image Segmentation
The hybrid architecture of convolutional neural networks (CNNs) and
Transformer are very popular for medical image segmentation. However, it
suffers from two challenges. First, although a CNNs branch can capture the
local image features using vanilla convolution, it cannot achieve adaptive
feature learning. Second, although a Transformer branch can capture the global
features, it ignores the channel and cross-dimensional self-attention,
resulting in a low segmentation accuracy on complex-content images. To address
these challenges, we propose a novel hybrid architecture of convolutional
neural networks hand in hand with vision Transformers (CiT-Net) for medical
image segmentation. Our network has two advantages. First, we design a dynamic
deformable convolution and apply it to the CNNs branch, which overcomes the
weak feature extraction ability due to fixed-size convolution kernels and the
stiff design of sharing kernel parameters among different inputs. Second, we
design a shifted-window adaptive complementary attention module and a compact
convolutional projection. We apply them to the Transformer branch to learn the
cross-dimensional long-term dependency for medical images. Experimental results
show that our CiT-Net provides better medical image segmentation results than
popular SOTA methods. Besides, our CiT-Net requires lower parameters and less
computational costs and does not rely on pre-training. The code is publicly
available at https://github.com/SR0920/CiT-Net
Directional Enhanced Probe for Side-Illumination Tip Enhanced Spectroscopy
We demonstrate a high-performance apertureless near-field probe made of a
tapered metal tip with a set of periodic shallow grooves near the apex. The
spontaneous emission from a single emitter near the tip is investigated
systematically for the side-illumination tip enhanced spectroscopy (TES). In
contrast with the bare tapered metal tip in conventional side-illumination TES,
the corrugated probe not only enhances strongly local excitation field but also
concentrates the emission directivity, which leads to high collection
efficiency and signal-to-noise ratio. In particular, we propose an asymmetric
TES tip based on two coupling nanorods with different length at the apex to
realize unidirectional enhanced emission rate from a single emitter.
Interestingly, we find that the radiation pattern is sensitive to the emission
wavelength and the emitter positions respective to the apex, which can result
in an increase of signal-to-noise ratio by suppressing undesired signal. The
proposed asymmetrical corrugated probe opens up a broad range of practical
applications, e.g. increasing the detection efficiency of tip enhanced
spectroscopy at the single-molecule level
Complement receptor 2 is expressed in neural progenitor cells and regulates adult hippocampal neurogenesis
Injury and inflammation are potent regulators of adult neurogenesis. As the complement system forms a key immune pathway that may also exert critical functions in neural development and neurodegeneration, we asked if complement receptors regulate neurogenesis. We discovered that complement receptor 2 (CR2), classically known as a co-receptor of the B lymphocyte antigen receptor, is expressed in adult neural progenitor cells (NPCs) of the dentate gyrus. Two of its ligands, C3d and interferon-α (IFN-α), inhibited proliferation of wildtype NPCs but not NPCs derived from mice lacking Cr2 (Cr2(−/−)) indicating functional Cr2 expression. Young and old Cr2(−/−) mice exhibited prominent increases in basal neurogenesis compared with wildtype littermates, while intracerebral injection of C3d resulted in fewer proliferating neuroblasts in wildtype than in Cr2(−/−) mice. We conclude that Cr2 regulates hippocampal neurogenesis and propose that increased C3d and IFN-α production associated with brain injury or viral infections may inhibit neurogenesis
From multi-omics approaches to personalized medicine in myocardial infarction
Myocardial infarction (MI) is a prevalent cardiovascular disease characterized by myocardial necrosis resulting from coronary artery ischemia and hypoxia, which can lead to severe complications such as arrhythmia, cardiac rupture, heart failure, and sudden death. Despite being a research hotspot, the etiological mechanism of MI remains unclear. The emergence and widespread use of omics technologies, including genomics, transcriptomics, proteomics, metabolomics, and other omics, have provided new opportunities for exploring the molecular mechanism of MI and identifying a large number of disease biomarkers. However, a single-omics approach has limitations in understanding the complex biological pathways of diseases. The multi-omics approach can reveal the interaction network among molecules at various levels and overcome the limitations of the single-omics approaches. This review focuses on the omics studies of MI, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, and other omics. The exploration extended into the domain of multi-omics integrative analysis, accompanied by a compilation of diverse online resources, databases, and tools conducive to these investigations. Additionally, we discussed the role and prospects of multi-omics approaches in personalized medicine, highlighting the potential for improving diagnosis, treatment, and prognosis of MI
A real-world study of anlotinib as third-line or above therapy in patients with her-2 negative metastatic breast cancer
BackgroundAntiangiogenic agents provides an optional treatment strategy for patients with metastatic breast cancer. The present study was conducted to evaluate the efficacy and safety of anlotinib as third-line or above therapy for patients with HER-2 negative metastatic breast cancer.MethodsPatients with HER-2 negative metastatic breast cancer who have failed from prior therapy and treated with anlotinib monotherapy or combined with chemotherapy or immunotherapy from June 2018 to December 2020 were retrospectively analyzed based on real-world clinical practice. The primary end point was progression free survival (PFS). Secondary end points included objective response rate (ORR), disease control rate (DCR), overall survival (OS) and safety.Results47 patients with HER-2 negative metastatic breast cancer received anlotinib monotherapy or combination therapy as third-line or above therapy. In the general population, 10 patients achieved PR, 25 patients had SD and 12 patients had PD. The overall ORR and DCR were 21.3% and 74.5%, respectively. Subgroup analysis suggested that there were no statistically significant differences in ORR and DCR with respect to HR status (positive vs. negative), treatment programs (monotherapy vs. combination) and treatment type in combination group (chemotherapy vs. immunotherapy). The patients who did not received previously anti-angiogenesis therapy had superior DCR (84.8% vs. 50.0%, P=0.012). Median PFS and OS were 5.0 months (95% CI=4.3-5.7) and 21.0 (95% CI=14.9-27.1) months, respectively. The PFS (6.5m vs. 3.5m, P=0.042)and OS (28.2m vs. 12.6m, P=0.040) were better in HR positive patients than HR negative patients. And simultaneously, patients who received anlotinib combination therapy obtained better PFS (5.5m vs. 3.0m, P=0.045). The incidence of Grade 3-4 adverse events(AEs) was 31.9%.ConclusionsAnlotinib monotherapy or combination therapy provide a viable third-line or above therapeutic strategy in patients with HER-2 negative metastatic breast cancer, a median PFS of 5.0 months was obtained with well tolerated toxicity
Small anisotropy of the lower critical field and -wave two-gap feature in single crystal LiFeAs
The in- and out-of-plane lower critical fields and magnetic penetration
depths for LiFeAs were examined. The anisotropy ratio is
smaller than the expected theoretical value, and increased slightly with
increasing temperature from 0.6 to . This small degree of anisotropy
was numerically confirmed by considering electron correlation effect. The
temperature dependence of the penetration depths followed a power
law() below 0.3, with 3.5 for both and
. Based on theoretical studies of iron-based superconductors, these
results suggest that the superconductivity of LiFeAs can be represented by an
extended -wave due to weak impurity scattering effect. And the
magnitudes of the two gaps were also evaluted by fitting the superfluid density
for both the in- and out-of-plane to the two-gap model. The estimated values
for the two gaps are consistent with the results of angle resolved
photoemission spectroscopy and specific heat experiments.Comment: 10 pages, 5 figure
A new method for the characterization of microcracks based on seepage characteristics
Microcracks are the main seepage channels and reservoir space for oil and gas in dense sandstone reservoirs, and the degree of development dominates the reservoir’s high and stable production capacity. A new method has been devised to address the lack of quantitative identification and characterization methods for microcrack networks. The method is based on core stress sensitivity, permeability anisotropy, and two-phase seepage rule testing. By improving upon the traditional black oil model, this method can accurately calculate the impact that microcracks of varying degrees of development have on the capacity of tight oil reservoirs. The study shows that 1) the higher the degree of microcrack development, the stronger the reservoir stress sensitivity and the greater the permeability anisotropy. As the degree of microcrack development increases, the irreducible water saturation decreases, the residual oil saturation gradually increases, and the oil–water two-phase co-infiltration zone becomes more extensive and smaller. The degree of microcrack development in tight reservoirs can be characterized based on the seepage characteristic parameters; 2) a microcrack characterization method and classification criteria have been established. It is based on stress sensitivity coefficients, permeability anisotropy parameters, and phase seepage characteristics in cores with different microcrack development degrees. For the first time, the method enables a macroscopic-level description of microcrack seepage; 3) numerical calculations show that the degree of microcrack development significantly affects the reservoir’s oil production and water production. The higher the degree of microcrack development, the higher the reservoir’s initial oil production and cumulative oil production. However, when the degree of microcrack development is too high, the microcracks are connected, thus exhibiting the nature of large fractures. This strengthens the bypassing communication effect and causes the microscopic inhomogeneity to strengthen, the oil production decreases rapidly, and water production increases quickly at the later stage. This research result enriches the reservoir microcrack characterization and evaluation system, which has essential theoretical guidance and practical significance for the rational and effective development of tight oil and tight sandstone gas
Integrated aquaculture contributes to the transfer of mcr-1 between animals and humans via the aquaculture supply chain
Background
Since its discovery in 2015, the mobile colistin resistance gene mcr-1 has been reported in bacteria from > 50 countries. Although aquaculture-associated bacteria may act as a significant reservoir for colistin resistance, systematic investigations of mcr-1 in the aquaculture supply chain are scarce.
Objectives
We investigated the presence of colistin resistance determinants in the aquaculture supply chain in south China and determined their characteristics and relationships.
Methods
A total of 250 samples were collected from a duck-fish integrated fishery, slaughter house, and market in Guangdong Province, China, in July 2017. Colistin-resistant bacteria were isolated on colistin-supplemented CHROMagar Orientation plates, and the species were identified by matrix-assisted laser desorption/ionization time-of-flight assay. The presence of mcr genes was confirmed by polymerase chain reaction analysis. We examined the minimum inhibitory concentrations (MICs) of 16 antimicrobial agents against the isolates using agar diffusion and broth microdilution methods. Whole-genome sequencing (WGS) was used to explore the molecular characteristics and relationships of mcr-1-positive Escherichia coli (MCRPEC).
Results
Overall, 143 (57.2%) colistin-resistant bacteria were isolated, of which, 56 (22.4%, including 54 Escherichia coli and two Klebsiella pneumoniae) and four Aeromonas species were positive for mcr-1 and mcr-3, respectively. The animal-derived MCRPEC were significantly more prevalent in integrated fishery samples (40.0%) than those in market (4.8%, P 90%) but were susceptible to carbapenems and tigecycline. WGS analysis suggested that mcr-1 was mainly contained on plasmids, including IncHI2 (29.6%), IncI2 (27.8%), IncX4 (14.8%), and IncP (11.1%). Genomic analysis suggested mcr-1 transmission via the aquatic food chain.
Conclusions
MCRPEC were highly prevalent in the aquaculture supply chain, with the isolates showing resistance to most antibiotics. The data suggested mcr-1 could be transferred to humans via the aquatic food chain. Taking the “One Health” perspective, aquaculture should be incorporated into systematic surveillance programs with animal, human, and environmental monitoring
- …