12,800 research outputs found
2,2′,4,4′,6,6′-Hexamethyl-N-(3-phthalimidopropyl)-N,N′-(propane-1,3-diyl)dibenzenesulfonamide
In the title compound, C32H38N3O6S2, an intermediate in the synthesis of polyamine drugs, the dihedral angle between the phenyl rings of the two 2,4,6-trimethylbenzenesulfonyl groups is 27.1 (3)°. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds, thereby forming an infinite one-dimensional chain propagating along [010]
Elevated lead levels in relation to low serum neuropeptide Y and adverse behavioral effects in preschool children with e-waste exposure
As a neurotoxicant, lead (Pb) primarily affects central nervous system, and particularly impacts developing brain. This study explores the associations of blood Pb level and children's behavioral health. A total of 213 preschool children aged 3-7 years old were recruited from Guiyu (the e-waste-exposed area) and Haojiang (the reference area). The behavioral health of children was assessed using the 'behavioral symptoms' subscale of the Strengths and Difficulties Questionnaire (SDQ). Results showed that there was a significant difference in percent of children categorized as "at risk" between Guiyu (48.2%) and Haojiang (13.9%) (p = 5.00 mu g/dL (high) than those with blood Pb level < 5.00 mu g/dL (low). After adjusting for confounding factors, children with lower NPY levels were at higher risk of having behavioral difficulties. In conclusion, Pb exposure in e-waste-exposed areas may lead to decrease in serum NPY and increase in the risk of children's behavioral problems. In addition, NPY may mediate the association between Pb exposure and behavioral difficulties. (C) 2020 Elsevier Ltd. All rights reserved
N,N′-Bis(2-cyanoethyl)-4,4′-dimethyl-N,N′-(butane-1,4-diyl)dibenzenesulfonamide
The complete molecule of the title compound, C24H30N4O4S2, is generated by a crystallographic inversion centre. In the crystal, weak C—H⋯O interactions link the molecules, forming infinite sheets
2-(3-Bromopropyl)isoindoline-1,3-dione
In the title compound, C11H10BrNO2, the dihedral angle between the five- and six-membered rings of the phthalamide system is 1.00 (16)°. There are no significant intermolecular interations except for van der Waals contacts
Decoupled Local Aggregation for Point Cloud Learning
The unstructured nature of point clouds demands that local aggregation be
adaptive to different local structures. Previous methods meet this by
explicitly embedding spatial relations into each aggregation process. Although
this coupled approach has been shown effective in generating clear semantics,
aggregation can be greatly slowed down due to repeated relation learning and
redundant computation to mix directional and point features. In this work, we
propose to decouple the explicit modelling of spatial relations from local
aggregation. We theoretically prove that basic neighbor pooling operations can
too function without loss of clarity in feature fusion, so long as essential
spatial information has been encoded in point features. As an instantiation of
decoupled local aggregation, we present DeLA, a lightweight point network,
where in each learning stage relative spatial encodings are first formed, and
only pointwise convolutions plus edge max-pooling are used for local
aggregation then. Further, a regularization term is employed to reduce
potential ambiguity through the prediction of relative coordinates.
Conceptually simple though, experimental results on five classic benchmarks
demonstrate that DeLA achieves state-of-the-art performance with reduced or
comparable latency. Specifically, DeLA achieves over 90\% overall accuracy on
ScanObjectNN and 74\% mIoU on S3DIS Area 5. Our code is available at
https://github.com/Matrix-ASC/DeLA
Learning a Stable Dynamic System with a Lyapunov Energy Function for Demonstratives Using Neural Networks
Autonomous Dynamic System (DS)-based algorithms hold a pivotal and
foundational role in the field of Learning from Demonstration (LfD).
Nevertheless, they confront the formidable challenge of striking a delicate
balance between achieving precision in learning and ensuring the overall
stability of the system. In response to this substantial challenge, this paper
introduces a novel DS algorithm rooted in neural network technology. This
algorithm not only possesses the capability to extract critical insights from
demonstration data but also demonstrates the capacity to learn a candidate
Lyapunov energy function that is consistent with the provided data. The model
presented in this paper employs a straightforward neural network architecture
that excels in fulfilling a dual objective: optimizing accuracy while
simultaneously preserving global stability. To comprehensively evaluate the
effectiveness of the proposed algorithm, rigorous assessments are conducted
using the LASA dataset, further reinforced by empirical validation through a
robotic experiment
Study on electromagnetically induced transparency effects in Dirac and VO hybrid material structure
In this paper, we present a metamaterial structure of Dirac and vanadium
dioxide and investigate its optical properties using the finite-difference
time-domain (FDTD) technique. Using the phase transition feature of vanadium
dioxide, the design can realize active tuning of the PIT effect at terahertz
frequency, thereby converting from a single PIT to a double PIT. When VO is
in the insulating state, the structure is symmetric to obtain a single-band PIT
effect; When VO is in the metallic state, the structure turns asymmetric to
realize a dual-band PIT effect. This design provides a reference direction for
the design of actively tunable metamaterials. Additionally, it is discovered
that the transparent window's resonant frequency and the Dirac material's Fermi
level in this structure have a somewhat linear relationship. In addition, the
structure achieves superior refractive index sensitivity in the terahertz band,
surpassing 1 THz/RIU. Consequently, the concept exhibits encouraging potential
for application in refractive index sensors and optical switches
Relations of blood lead levels to echocardiographic left ventricular structure and function in preschool children
Lead (Pb) has been proved to exert adverse effect on human cardiovascular system. However, the cardiotoxicity of Pb on children is still unclear. The aim of this study was to evaluate left ventricular (LV) structure and function, by using echocardiographic indices, in order to elucidate the effect of Pb on low-grade inflammation related to left ventricle in healthy preschool children. We recruited a total of 486 preschool children, 310 from Guiyu (e-waste-exposed area) and 176 from Haojiang (reference area). Blood Pb levels, complete blood counts, and LV parameters were evaluated. Associations between blood Pb levels and LV parameters and peripheral leukocyte counts were analyzed using linear regression models. The median blood level of Pb and the counts of white blood cells (WBCs), monocytes, and neutrophils were higher in exposed group. In addition, the exposed group showed smaller left ventricle (including interventricular septum, LV posterior wall, and LV mass index) and impaired LV systolic function (including LV fractional shortening and LV ejection fraction) regardless gender. After adjustment for confounding factors, elevated blood Pb levels were significantly associated with higher counts of WBCs and neutrophils, and lower levels of LV parameters. Furthermore, counts of WBCs, monocytes, and neutrophils were negatively correlated with LV parameters. Taken together, smaller left ventricle and impaired systolic function were found in e-waste-exposed children and associated with chronic low-grade inflammation and elevated blood Pb levels. It indicates that the heart health of e-waste-exposed children is at risk due to the long-term environmental chemical insults. (C) 2020 Elsevier Ltd. All rights reserved
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