268 research outputs found
MMSE Reconstruction for 3D Freehand Ultrasound Imaging
The reconstruction of 3D ultrasound (US) images from
mechanically registered, but otherwise irregularly positioned,
B-scan slices is of great interest in image guided therapy procedures.
Conventional 3D ultrasound algorithms have low computational complexity, but the reconstructed volume suffers from severe speckle contamination. Furthermore, the current method cannot reconstruct uniform high-resolution data from several low-resolution B-scans. In this paper, the minimum mean-squared error (MMSE) method is applied to 3D ultrasound reconstruction. Data redundancies due to overlapping samples as well as correlation of the target and speckle are naturally accounted for in the MMSE reconstruction algorithm. Thus, the reconstruction process unifies the interpolation and spatial compounding. Simulation results for synthetic US images are presented to demonstrate the excellent reconstruction
Recent Progress on the Molecular Mechanisms of Anti-invasive and Metastatic Chinese Medicines for Cancer Therapy
Despite of the recent advances in diagnostic and therapeutic approaches, cancer remains as the leading cause of death worldly with diverse causal factors regarding genes and environment. Invasion and metastasis, as one of the most important hallmarks for cancer, have restrained the successful clinical therapy and are the primary causes of death among cancer patients. So far, most chemotherapeutic drugs are not effective for metastatic cancer due to drug resistance and serious side effects. Therefore, it is urgently essential to develop more effective therapeutic methods. Owing to their diverse biological activities and low toxicity, naturally active compounds derived from Chinese medicines, as a complementary and alternative approach, are reported to promote the therapeutic index and provoked as an excellent source for candidates of anti-metastatic drugs. With the rapid development of molecular biology techniques, the molecular mechanisms of the effects of potential anti-invasive and metastatic Chinese medicines are gradually elucidated. This chapter reviews the potential anti-invasive and metastatic mechanisms of naturally active compounds from Chinese medicines, including suppression of EMT, proteases and cancer-induced angiogenesis, anoikis regulation of circulating tumor cells and regulation of miRNA-mediated gene expression, providing scientific evidence for clinically using Chinese medicines in the field of cancer therapy
Chinese Medicines for Cancer Treatment from the Metabolomics Perspective
Cancer is one of the most prevalent diseases all over the world with poor prognosis and the development of novel therapeutic strategies is still urgently needed. The large amount of successful experiences in fighting against cancer-like diseases with Chinese medicine has suggested it as a great source of alternative treatments to human cancers. Cancer cells have been shown to own a predominantly unique metabolic phenotype to facilitate their rapid proliferation. Metabolic reprogramming is a remarkable hallmark of cancer and therapies targeting cancer metabolism can be highly specific and effective. Based on the sophisticated study of small molecule metabolites, metabolomics can provide us valuable information on dynamically metabolic responses of living systems to certain environmental condition. In this chapter, we systematically reviewed recent studies on metabolism-targeting anticancer therapies based on metabolomics in terms of glucose, lipid, amino acid, and nucleotide metabolisms and other altered metabolisms, with special emphasis on the potential of metabolic treatment with pure compounds, herb extracts, and formulations from Chinese medicines. The trends of future development of metabolism-targeting anticancer therapies were also discussed. Overall, the elucidation of the underlying molecular mechanism of metabolism-targeting pharmacologic therapies will provide us a new insight to develop novel therapeutics for cancer treatment
Global Context Aware Convolutions for 3D Point Cloud Understanding
Recent advances in deep learning for 3D point clouds have shown great
promises in scene understanding tasks thanks to the introduction of convolution
operators to consume 3D point clouds directly in a neural network. Point cloud
data, however, could have arbitrary rotations, especially those acquired from
3D scanning. Recent works show that it is possible to design point cloud
convolutions with rotation invariance property, but such methods generally do
not perform as well as translation-invariant only convolution. We found that a
key reason is that compared to point coordinates, rotation-invariant features
consumed by point cloud convolution are not as distinctive. To address this
problem, we propose a novel convolution operator that enhances feature
distinction by integrating global context information from the input point
cloud to the convolution. To this end, a globally weighted local reference
frame is constructed in each point neighborhood in which the local point set is
decomposed into bins. Anchor points are generated in each bin to represent
global shape features. A convolution can then be performed to transform the
points and anchor features into final rotation-invariant features. We conduct
several experiments on point cloud classification, part segmentation, shape
retrieval, and normals estimation to evaluate our convolution, which achieves
state-of-the-art accuracy under challenging rotations
Circular Accessible Depth: A Robust Traversability Representation for UGV Navigation
In this paper, we present the Circular Accessible Depth (CAD), a robust
traversability representation for an unmanned ground vehicle (UGV) to learn
traversability in various scenarios containing irregular obstacles. To predict
CAD, we propose a neural network, namely CADNet, with an attention-based
multi-frame point cloud fusion module, Stability-Attention Module (SAM), to
encode the spatial features from point clouds captured by LiDAR. CAD is
designed based on the polar coordinate system and focuses on predicting the
border of traversable area. Since it encodes the spatial information of the
surrounding environment, which enables a semi-supervised learning for the
CADNet, and thus desirably avoids annotating a large amount of data. Extensive
experiments demonstrate that CAD outperforms baselines in terms of robustness
and precision. We also implement our method on a real UGV and show that it
performs well in real-world scenarios.Comment: 13 pages, 8 figure
Fluorescent Probes for Molecular Imaging of ROS/RNS Species in Living Systems
Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are highly reactive species which play crucial roles in many fundamental physiological processes including cellular signalling pathways. Over-production of these reactive species by various stimuli leads to cellular oxidative stress which is linked to various disease conditions. Therefore, the development of novel detection methods for ROS and RNS is of great interest and indispensable for monitoring the dynamic changes of ROS and RNS in cells and for elucidating their mechanisms of trafficking and connections to diseases. We have been recently developing various fluorescent sensors which can selectively detect metal ions, ROS or RNS species in live cells or animals. Our turn-on profluorescent sensors are capable of imaging oxidative stress promoted by metal and H2O2 (i.e. the Fenton Reaction conditions) in living cells (Chem Commun 2010); our highly selective and sensitive iron sensors can image the endogenous exchangeable iron pools and their dynamic changes with subcellular resolution in living neuronal cells (ChemBioChem 2012 and unpublished data), and so do our superoxide sensors (ChemBioChem 2012 and unpublished data). Moreover, we have recently developed nitric oxide (NO) sensors for molecular imaging of stimulated NO production in live cells with subcellular resolution as well as novel near infra red (NIR) sensors for NO imaging in live animals
Genetic Dissection of Cardiac Remodeling in an Isoproterenol-Induced Heart Failure Mouse Model.
We aimed to understand the genetic control of cardiac remodeling using an isoproterenol-induced heart failure model in mice, which allowed control of confounding factors in an experimental setting. We characterized the changes in cardiac structure and function in response to chronic isoproterenol infusion using echocardiography in a panel of 104 inbred mouse strains. We showed that cardiac structure and function, whether under normal or stress conditions, has a strong genetic component, with heritability estimates of left ventricular mass between 61% and 81%. Association analyses of cardiac remodeling traits, corrected for population structure, body size and heart rate, revealed 17 genome-wide significant loci, including several loci containing previously implicated genes. Cardiac tissue gene expression profiling, expression quantitative trait loci, expression-phenotype correlation, and coding sequence variation analyses were performed to prioritize candidate genes and to generate hypotheses for downstream mechanistic studies. Using this approach, we have validated a novel gene, Myh14, as a negative regulator of ISO-induced left ventricular mass hypertrophy in an in vivo mouse model and demonstrated the up-regulation of immediate early gene Myc, fetal gene Nppb, and fibrosis gene Lgals3 in ISO-treated Myh14 deficient hearts compared to controls
Nowhere to Go: Benchmarking Multi-robot Collaboration in Target Trapping Environment
Collaboration is one of the most important factors in multi-robot systems.
Considering certain real-world applications and to further promote its
development, we propose a new benchmark to evaluate multi-robot collaboration
in Target Trapping Environment (T2E). In T2E, two kinds of robots (called
captor robot and target robot) share the same space. The captors aim to catch
the target collaboratively, while the target will try to escape from the trap.
Both the trapping and escaping process can use the environment layout to help
achieve the corresponding objective, which requires high collaboration between
robots and the utilization of the environment. For the benchmark, we present
and evaluate multiple learning-based baselines in T2E, and provide insights
into regimes of multi-robot collaboration. We also make our benchmark publicly
available and encourage researchers from related robotics disciplines to
propose, evaluate, and compare their solutions in this benchmark. Our project
is released at https://github.com/Dr-Xiaogaren/T2E
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