299 research outputs found
Angle-dependent magnetoresistance as a sensitive probe of the charge density wave in quasi-one-dimensional semimetal TaNiSe
The behavior of charge density wave (CDW) in an external magnetic field is
dictated by both orbital and Pauli (Zeeman) effects. A quasi-one-dimensional
(Q1D) system features Q1D Fermi surfaces that allow these effects to be
distinguished, which in turn can provide sensitive probe to the underlying
electronic states. Here we studied the field dependence of an incommensurate
CDW in a transition-metal chalcogenide Ta2NiSe7 with a Q1D chain structure. The
angle-dependent magnetoresistance (MR) is found to be very sensitive to the
relative orientation between the magnetic field and the chain direction. With
an applied current fixed along the b axis (the chain direction), the
angle-dependent MR shows a striking change of the symmetry below T_CDW only for
a rotating magnetic field in the ac plane. In contrast, the symmetry axis
remains unchanged for other configurations (H in ab and bc plane). The orbital
effect conforms to the lattice symmetry, while Pauli effect in the form of
{\mu}B B / v_F can be responsible for such symmetry change, provided that the
Fermi velocity v_F is significantly anisotropic and the nesting vector changes
in a magnetic field, which is corroborated by our first-principles
calculations. Our results show that the angle-dependent MR is a sensitive
transport probe of CDW and can be useful for the study of low-dimensional
systems in general
Deep segmentation networks predict survival of non-small cell lung cancer
Non-small-cell lung cancer (NSCLC) represents approximately 80-85% of lung
cancer diagnoses and is the leading cause of cancer-related death worldwide.
Recent studies indicate that image-based radiomics features from positron
emission tomography-computed tomography (PET/CT) images have predictive power
on NSCLC outcomes. To this end, easily calculated functional features such as
the maximum and the mean of standard uptake value (SUV) and total lesion
glycolysis (TLG) are most commonly used for NSCLC prognostication, but their
prognostic value remains controversial. Meanwhile, convolutional neural
networks (CNN) are rapidly emerging as a new premise for cancer image analysis,
with significantly enhanced predictive power compared to other hand-crafted
radiomics features. Here we show that CNN trained to perform the tumor
segmentation task, with no other information than physician contours, identify
a rich set of survival-related image features with remarkable prognostic value.
In a retrospective study on 96 NSCLC patients before stereotactic-body
radiotherapy (SBRT), we found that the CNN segmentation algorithm (U-Net)
trained for tumor segmentation in PET/CT images, contained features having
strong correlation with 2- and 5-year overall and disease-specific survivals.
The U-net algorithm has not seen any other clinical information (e.g. survival,
age, smoking history) than the images and the corresponding tumor contours
provided by physicians. Furthermore, through visualization of the U-Net, we
also found convincing evidence that the regions of progression appear to match
with the regions where the U-Net features identified patterns that predicted
higher likelihood of death. We anticipate our findings will be a starting point
for more sophisticated non-intrusive patient specific cancer prognosis
determination
SongRewriter: A Chinese Song Rewriting System with Controllable Content and Rhyme Scheme
Although lyrics generation has achieved significant progress in recent years,
it has limited practical applications because the generated lyrics cannot be
performed without composing compatible melodies. In this work, we bridge this
practical gap by proposing a song rewriting system which rewrites the lyrics of
an existing song such that the generated lyrics are compatible with the rhythm
of the existing melody and thus singable. In particular, we propose
SongRewriter, a controllable Chinese lyric generation and editing system which
assists users without prior knowledge of melody composition. The system is
trained by a randomized multi-level masking strategy which produces a unified
model for generating entirely new lyrics or editing a few fragments. To improve
the controllabiliy of the generation process, we further incorporate a keyword
prompt to control the lexical choices of the content and propose novel decoding
constraints and a vowel modeling task to enable flexible end and internal rhyme
schemes. While prior rhyming metrics are mainly for rap lyrics, we propose
three novel rhyming evaluation metrics for song lyrics. Both automatic and
human evaluations show that the proposed model performs better than the
state-of-the-art models in both contents and rhyming quality. Our code and
models implemented in MindSpore Lite tool will be available
Embedded Spectral Descriptors: Learning the Point-Wise Correspondence Metric Via Siamese Neural Networks
A Robust and Informative Local Shape Descriptor Plays an Important Role in Mesh Registration. in This Regard, Spectral Descriptors that Are based on the Spectrum of the Laplace-Beltrami Operator Have Been a Popular Subject of Research for the Last Decade Due to their Advantageous Properties, Such as Isometry Invariance. Despite Such, However, Spectral Descriptors Often Fail to Give a Correct Similarity Measure for Nonisometric Cases Where the Metric Distortion between the Models is Large. Hence, They Are Not Reliable for Correspondence Matching Problems When the Models Are Not Isometric. in This Paper, it is Proposed a Method to Improve the Similarity Metric of Spectral Descriptors for Correspondence Matching Problems. We Embed a Spectral Shape Descriptor into a Different Metric Space Where the Euclidean Distance between the Elements Directly Indicates the Geometric Dissimilarity. We Design and Train a Siamese Neural Network to Find Such an Embedding, Where the Embedded Descriptors Are Promoted to Rearrange based on the Geometric Similarity. We Demonstrate Our Approach Can Significantly Enhance the Performance of the Conventional Spectral Descriptors by the Simple Augmentation Achieved Via the Siamese Neural Network in Comparison to Other State-Of-The-Art Methods
ZerNet: Convolutional Neural Networks on Arbitrary Surfaces via Zernike Local Tangent Space Estimation
In this paper, we propose a novel formulation to extend CNNs to
two-dimensional (2D) manifolds using orthogonal basis functions, called Zernike
polynomials. In many areas, geometric features play a key role in understanding
scientific phenomena. Thus, an ability to codify geometric features into a
mathematical quantity can be critical. Recently, convolutional neural networks
(CNNs) have demonstrated the promising capability of extracting and codifying
features from visual information. However, the progress has been concentrated
in computer vision applications where there exists an inherent grid-like
structure. In contrast, many geometry processing problems are defined on curved
surfaces, and the generalization of CNNs is not quite trivial. The difficulties
are rooted in the lack of key ingredients such as the canonical grid-like
representation, the notion of consistent orientation, and a compatible local
topology across the domain. In this paper, we prove that the convolution of two
functions can be represented as a simple dot product between Zernike polynomial
coefficients; and the rotation of a convolution kernel is essentially a set of
2-by-2 rotation matrices applied to the coefficients. As such, the key
contribution of this work resides in a concise but rigorous mathematical
generalization of the CNN building blocks
Chain of Agents: Large Language Models Collaborating on Long-Context Tasks
Addressing the challenge of effectively processing long contexts has become a
critical issue for Large Language Models (LLMs). Two common strategies have
emerged: 1) reducing the input length, such as retrieving relevant chunks by
Retrieval-Augmented Generation (RAG), and 2) expanding the context window limit
of LLMs. However, both strategies have drawbacks: input reduction has no
guarantee of covering the part with needed information, while window extension
struggles with focusing on the pertinent information for solving the task. To
mitigate these limitations, we propose Chain-of-Agents (CoA), a novel framework
that harnesses multi-agent collaboration through natural language to enable
information aggregation and context reasoning across various LLMs over
long-context tasks. CoA consists of multiple worker agents who sequentially
communicate to handle different segmented portions of the text, followed by a
manager agent who synthesizes these contributions into a coherent final output.
CoA processes the entire input by interleaving reading and reasoning, and it
mitigates long context focus issues by assigning each agent a short context. We
perform comprehensive evaluation of CoA on a wide range of long-context tasks
in question answering, summarization, and code completion, demonstrating
significant improvements by up to 10% over strong baselines of RAG,
Full-Context, and multi-agent LLMs.Comment: 19 pages, 6 figure
Orbital Expansion Variational Quantum Eigensolver: Enabling Efficient Simulation of Molecules with Shallow Quantum Circuit
In the noisy-intermediate-scale-quantum era, Variational Quantum Eigensolver
(VQE) is a promising method to study ground state properties in quantum
chemistry, materials science, and condensed physics. However, general quantum
eigensolvers are lack of systematical improvability, and achieve rigorous
convergence is generally hard in practice, especially in solving
strong-correlated systems. Here, we propose an Orbital Expansion VQE~(OE-VQE)
framework to construct an efficient convergence path. The path starts from a
highly correlated compact active space and rapidly expands and converges to the
ground state, enabling simulating ground states with much shallower quantum
circuits. We benchmark the OE-VQE on a series of typical molecules including
H-chain, H-ring and N, and the simulation results show that
proposed convergence paths dramatically enhance the performance of general
quantum eigensolvers.Comment: Wu et al 2023 Quantum Sci. Techno
A novel trifunctional IgG-like bispecific antibody to inhibit HIV-1 infection and enhance lysis of HIV by targeting activation of complement
BACKGROUND: The complement system is not only a key component of innate immunity but also provides a first line of defense against invading pathogens, especially for viral pathogens. Human immunodeficiency virus (HIV), however, possesses several mechanisms to evade complement-mediated lysis (CoML) and exploit the complement system to enhance viral infectivity. Responsible for this intrinsic resistance against complement-mediated virolysis are complement regulatory membrane proteins derived from the host cell that inherently downregulates complement activation at several stages of the cascade. In addition, HIV is protected from complement-mediated lysis by binding soluble factor H (fH) through the viral envelope proteins, gp120 and gp41. Whereas inhibition of complement activity is the desired outcome in the vast majority of therapeutic approaches, there is a broader potential for complement-mediated inhibition of HIV by complement local stimulation. PRESENTATION OF THE HYPOTHESIS: Our previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that another new activator of complement, consisting of two dsFv (against gp120 and against C3d respectively) linked to a complement-activating human IgG1 Fc domain ((anti-gp120 × anti-C3d)-Fc), can not only target and amplify complement activation on HIV virions for enhancing the efficiency of HIV lysis, but also reduce the infectivity of HIV through blocking the gp120 and C3d on the surface of HIV. TESTING THE HYPOTHESIS: Our hypothesis was tested using cell-free HIV-1 virions cultivated in vitro and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified (anti-gp120 × anti-C3d)-Fc proteins. As a control group, viruses were incubated with normal human serum under the same conditions. Virus neutralization assays were used to estimate the degree of (anti-gp120 × anti-C3d)-Fc lysis of HIV compared to untreated virus. IMPLICATIONS OF THE HYPOTHESIS: The targeted complement activator, (anti-gp120 × anti-C3d)-Fc, can be used as a novel approach to HIV therapy by abrogating the complement-enhanced HIV infection of cells
Age-related sensitivity and pathological differences in infections by 2009 pandemic influenza A (H1N1) virus
<p>Abstract</p> <p>Background</p> <p>The highly pandemic 2009 influenza A H1N1 virus infection showed distinguished skewed age distribution with majority of infection and death in children and young adults. Although previous exposure to related antigen has been proposed as an explanation, the mechanism of age protection is still unknown.</p> <p>Methods</p> <p>In this study, murine model of different ages were inoculated intranasally with H1N1 (A/Beijing/501/09) virus and the susceptibility and pathological response to 2009 H1N1 infection were investigated.</p> <p>Results</p> <p>Our results showed that the younger mice had higher mortality rate when infected with the same dose of virus and the lethal dose increased with age. Immunohistochemical staining of H1N1 antigens in mice lung indicated infection was in the lower respiratory tract. Most bronchial and bronchiolar epithelial cells in 4-week mice were infected while only a minor percentage of those cells in 6-month and 1-year old mice did. The young mice developed much more severe lung lesions and had higher virus load in lung than the two older groups of mice while older mice formed more inducible bronchus-associated lymphoid tissue in their lungs and more severe damage in spleen.</p> <p>Conclusions</p> <p>These results suggest that young individuals are more sensitive to H1N1 infection and have less protective immune responses than older adults. The age factor should be considered when studying the pathogenesis and transmission of influenza virus and formulating strategies on vaccination and treatment.</p
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