Distance-Restricted Folklore Weisfeiler-Leman GNNs with Provable Cycle Counting Power

The ability of graph neural networks (GNNs) to count certain graph substructures, especially cycles, is important for the success of GNNs on a wide range of tasks. It has been recently used as a popular metric for evaluating the expressive power of GNNs. Many of the proposed GNN models with provable cycle counting power are based on subgraph GNNs, i.e., extracting a bag of subgraphs from the input graph, generating representations for each subgraph, and using them to augment the representation of the input graph. However, those methods require heavy preprocessing, and suffer from high time and memory costs. In this paper, we overcome the aforementioned limitations of subgraph GNNs by proposing a novel class of GNNs -- $d$-Distance-Restricted FWL(2) GNNs, or $d$-DRFWL(2) GNNs. $d$-DRFWL(2) GNNs use node pairs whose mutual distances are at most $d$ as the units for message passing to balance the expressive power and complexity. By performing message passing among distance-restricted node pairs in the original graph, $d$-DRFWL(2) GNNs avoid the expensive subgraph extraction operations in subgraph GNNs, making both the time and space complexity lower. We theoretically show that the discriminative power of $d$-DRFWL(2) GNNs strictly increases as $d$ increases. More importantly, $d$-DRFWL(2) GNNs have provably strong cycle counting power even with $d=2$: they can count all 3, 4, 5, 6-cycles. Since 6-cycles (e.g., benzene rings) are ubiquitous in organic molecules, being able to detect and count them is crucial for achieving robust and generalizable performance on molecular tasks. Experiments on both synthetic datasets and molecular datasets verify our theory. To the best of our knowledge, our model is the most efficient GNN model to date (both theoretically and empirically) that can count up to 6-cycles

In situ Chromatin Interaction Analysis Using Paired-End Tag Sequencing.

Chromatin Interaction Analysis Using Paired-End Tag Sequencing (ChIA-PET) is an established method to map protein-mediated chromatin interactions. A limitation, however, is that it requires a hundred million cells per experiment, which hampers its broad application in biomedical research, particularly in studies in which it is impractical to obtain a large number of cells from rare samples. To reduce the required input cell number while retaining high data quality, we developed an in situ ChIA-PET protocol, which requires as few as 1 million cells. Here, we describe detailed step-by-step procedures for performing in situ ChIA-PET from cultured cells, including both an experimental protocol for sample preparation and data generation and a computational protocol for data processing and visualization using the ChIA-PIPE pipeline. As the protocol significantly simplifies the experimental procedure, reduces ligation noise, and decreases the required input of cells compared to previous versions of ChIA-PET protocols, it can be applied to generate high-resolution chromatin contact maps mediated by various protein factors for a wide range of human and mouse primary cells. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Sample preparation and data generation Support Protocol: Bridge linker preparation Basic Protocol 2: Data processing and visualization

Spectral characterizations of graphs with at most two (signless) Laplacian eigenvalues greater than 2

In this paper we consider the graphs having at most two (signless) Laplacian eigenvalues greater than 2. We prove that all these graphs are determined by the spectrum of their Laplacian matrix, and that all these graphs except the star on four vertices are determined by the spectrum of their signless Laplacian matrix

Comparative Study of Pore Structure Characteristics between Mudstone and Coal under Different Particle Size Conditions

In order to investigate the difference of pore structure characteristics between mudstone and coal under different particle size conditions, samples acquired from Henan province were smashed and screened into three different particle sizes (20–40, 80–100, and >200 mesh) to conduct the experiments, using the high-pressure mercury intrusion porosimetry (MIP) and low-temperature N2 adsorption (LT-N2A) techniques. The results demonstrated that the proportion of open pores or semi-enclosed pores increased, and the pores became preferable contacted each other for both mudstone and coal during the crushing process. These variations of pore structure characteristics in the coal were beneficial to methane storage and migration. The total specific surface areas and pore volumes all showed a tendency of increasing continually for both mudstone and coal, as the particle sizes decreased from the LT-N2A test. The mudstone and coal were non-rigid aggregates with micropores, plate-shaped pores, and slit-shaped pores developed inside. The effect of the crushing process on the pore shape for the mudstone and coal was inappreciable. Moreover, the influence of the particle sizes on the mesopore was the most significant, followed by the macropore; and on the micropore, the influence was negligible for both mudstone and coal. The crushing process only had a significant impact on the pore structure of mudstone with a particle size of less than 100 mesh, while it could still alter the pore structure of coal with a particle size of larger than 100 mesh. It is believed that this work has a significant meaning to explore the diffusion and migration rules of coal-bed methane in coal

Substance use and self-medication during pregnancy and associations with socio-demographic data: A cross-sectional survey

Objective: To identify women vulnerable to substance use and self-medication during pregnancy based on associations with socio-demographic data. Methods: Data were collected in person, with self-developed questionnaires, from pregnant women (n = 422) in Chengdu, China, from July to November 2012. Multivariate logistic regression analysis was used to reveal associations with socio-demographic parameters. Results: Higher educational background, being employed, and higher educational background of the mother were associated with a 37% [odds ratio (OR):0.63, 95%CI:0.45–0.89], 65% (OR:0.35, 95%CI:0.13–0.94), and 29% (OR: 0.71, 95%CI:0.53–0.96) less likelihood of alcohol use, respectively. Adverse pregnancy outcome was associated with a 2.13-fold (OR: 2.13, 95%CI: 1.07–4.25) greater likelihood of alcohol use. Young age and higher educational background were associated with an 11% (OR: 0.89, 95%CI: 0.81–0.98) and 31% (OR:0.69, 95%CI:0.49–0.98) less likelihood of cigarette smoking, respectively. Conclusion: Socio-demographic parameters were associated with substance use during pregnancy and warrants targeted health education provided by nurses to pregnant women

Comparative Study of Pore Structure Characteristics between Mudstone and Coal under Different Particle Size Conditions

In order to investigate the difference of pore structure characteristics between mudstone and coal under different particle size conditions, samples acquired from Henan province were smashed and screened into three different particle sizes (20–40, 80–100, and >200 mesh) to conduct the experiments, using the high-pressure mercury intrusion porosimetry (MIP) and low-temperature N2 adsorption (LT-N2A) techniques. The results demonstrated that the proportion of open pores or semi-enclosed pores increased, and the pores became preferable contacted each other for both mudstone and coal during the crushing process. These variations of pore structure characteristics in the coal were beneficial to methane storage and migration. The total specific surface areas and pore volumes all showed a tendency of increasing continually for both mudstone and coal, as the particle sizes decreased from the LT-N2A test. The mudstone and coal were non-rigid aggregates with micropores, plate-shaped pores, and slit-shaped pores developed inside. The effect of the crushing process on the pore shape for the mudstone and coal was inappreciable. Moreover, the influence of the particle sizes on the mesopore was the most significant, followed by the macropore; and on the micropore, the influence was negligible for both mudstone and coal. The crushing process only had a significant impact on the pore structure of mudstone with a particle size of less than 100 mesh, while it could still alter the pore structure of coal with a particle size of larger than 100 mesh. It is believed that this work has a significant meaning to explore the diffusion and migration rules of coal-bed methane in coal

The Enrichment and Distribution of Trifloxystrobin in Medaka Fish

In order to evaluate the safety of trifloxystrobin in environment and non-target organisms, the enrichment and distribution of trifloxystrobin in Medaka (Oryzias latipes) were studied in this experiment. Medaka were exposed in the water containing 0.1 μg/L, 1 μg/L, 10 μg/L and 100 μg/L trifloxystrobin continuously for 21 days. The results indicated that in female, the concentration order was as follows: fat > liver > intestine > gonad > flesh; in male, the concentration order was as follows: fat > intestine > liver > flesh in the low concentration exposure group with 0.1 μg/L and 1 μg/L, while the concentration order was as follows: fat > liver > intestine > flesh in the high concentration exposure group with 10 μg/L and 100 μg/L. This study provides important data support and theoretical basis for predicting the behavior of trifloxystrobin in the environment, evaluating the environmental safety of trifloxystrobin and guiding the use of drugs

High-performance Kerr microresonator optical parametric oscillator on a silicon chip

Flexible and coherent light generation is of paramount importance to enable new functionalities in integrated silicon photonics. Here the authors, develop an optical parametric oscillator with high conversion efficiency and high output power, based on the third order nonlinearity in a silicon nitride microresonato