216 research outputs found
NOMA-aided Joint Communication, Sensing, and Multi-tier Computing Systems
A non-orthogonal multiple access (NOMA)-aided joint communication, sensing,
and multi-tier computing (JCSMC) framework is proposed. In this framework, a
multi-functional base station (BS) carries out target sensing, while providing
edge computing services to the nearby users. To enhance the computation
efficiency, the multi-tier computing structure is exploited, where the BS can
further offload the computation tasks to a powerful Cloud server (CS). The
potential benefits of employing NOMA in the proposed JCSMC framework are
investigated, which can maximize the computation offloading capacity and
suppress the inter-function interference. Based on the proposed framework, the
transmit beamformer of the BS and computation resource allocation at the BS and
the CS are jointly optimized to maximize the computation rate subject to the
communication-computation causality and the sensing quality constraints. Both
partial and binary computation offloading modes are considered: 1) For the
partial offloading mode, a weighted minimum mean square error based alternating
optimization algorithm is proposed to solve the corresponding non-convex
optimization problem. It is proved that a KKT optimal solution can be obtained;
2) For the binary offloading mode, the resultant highly-coupled mixed-integer
optimization problem is first transformed to an equivalent but more tractable
form. Then, the reformulated problem is solved by utilizing the alternating
direction method of multipliers approach to obtain a nearly optimal solution.
Finally, numerical results verify the effectiveness of the proposed algorithms
and the proposed NOMA-aided JCSMC frameworkComment: 30 pages, 8 figure
The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China
Background The pastoral area of the eastern Tibetan plateau is a very important human echinococcosis endemic region. Domestic dogs are the main definitive host for the transmission of Echinococcus granulosus sensu lato (s.1.) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control program has been implemented since 2015 in Shiqu County, Sichuan, China, The objective of this investigation was to evaluate its effect on Echinococcus spp. prevalence in dogs. Methods We surveyed 69 households with 84 owned dogs, for dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples, consisting of 75 from owned dogs and 30 unknown dog fecal samples were collected between 2015 and 2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significantly relevant factors to canine echinococcosis prevalence in dogs. Results The overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually detected during the entire research period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus prevalence was as high as E. multilocularis , although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha Village in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24h per day, and the avoidance of dogs feeding on livestock viscera are significant measures to prevent canine echinococcosis infection in owned dogs. Conclusion Carrying out a canine echinococcosis prevention and control program can significantly decrease the Echinococcus prevalence. The potential contact between leashed dogs and wild small mammals is still a risk to re-infect owned dogs. This study shows that the long term application of regular dog dosing in the vast remote echinococcosis endemic areas of west China is still challenging
Crystal Structure of Levansucrase from the Gram-Negative Bacterium Brenneria Provides Insights into Its Product Size Specificity
Microbial levansucrases (LSs, EC 2.4.1.10) have been widely studied for the synthesis of β-(2,6)-fructans (levan) from sucrose. LSs synthesize levan-type fructo-oligosaccharides, high-molecular-mass levan polymer or combinations of both. Here, we report crystal structures of LS from the G-bacterium Brenneria sp. EniD 312 (Brs-LS) in its apo form, as well as of two mutants (A154S, H327A) targeting positions known to affect LS reaction specificity. In addition, we report a structure of Brs-LS complexed with sucrose, the first crystal structure of a G-LS with a bound substrate. The overall structure of Brs-LS is similar to that of G- and G+-LSs, with the nucleophile (D68), transition stabilizer (D225), and a general acid/base (E309) in its active site. The H327A mutant lacks an essential interaction with glucosyl moieties of bound substrates in subsite +1, explaining the observed smaller products synthesized by this mutant. The A154S mutation affects the hydrogen-bond network around the transition stabilizing residue (D225) and the nucleophile (D68), and may affect the affinity of the enzyme for sucrose such that it becomes less effective in transfructosylation. Taken together, this study provides novel insights into the roles of structural elements and residues in the product specificity of LSs
Rapamycin Inhibits ALDH Activity, Resistance to Oxidative Stress, and Metastatic Potential in Murine Osteosarcoma Cells
ALDH Activity Correlates with Metastatic Potential in Primary Sarcomas of Bone.
Osteosarcoma (OS), chondrosarcoma (CSA), and Ewings sarcoma (ES) are the most common primary malignancies of bone, and are rare diseases. As with all sarcomas, the prognosis of these diseases ultimately depends on the presence of metastatic disease. Survival is therefore closely linked with the biology and metastatic potential of a particular bone tumor's cells. Here we describe a significant correlation of aldehyde dehydrogenase (ALDH) activity and the presence/absence of distant metastases in ten consecutive cases of human bone sarcomas. Additionally, cultured human CSA cells, which are historically chemo- and radio-resistant, may be sensitive to the ALDH inhibitor, disulfiram. While it is premature to draw broad conclusions from such a small series, the importance of ALDH activity and inhibition in the metastatic potential of primary bone sarcomas should be investigated further
Self-compression of stimulated Raman backscattering by flying focus
A novel regime of self-compression is proposed for plasma-based backward
Raman amplification(BRA) upon flying focus. By using a pumping focus moving
with a speed equal to the group velocity of stimulated Raman
backscattering(SRBS), only a short part of SRBS which does always synchronize
with the flying focus can be amplified. Due to the asymmetrical amplification,
the pulse can be directly compressed in the linear stage of BRA. Therefore,
instead of a short pulse, the Raman spontaneous or a long pulse can seed the
BRA amplifiers. The regime is supported by the 2D particle-in-cell(PIC)
simulation without a seed, presenting that the pump pulse is compressed from
26ps to 116fs, with an output amplitude comparable with the case of a
well-synchronized short seed. This method provides a significant way to
simplify the Raman amplifiers and overcome the issue of synchronization jitter
between the pump and the seed
Retinal Targets ALDH Positive Cancer Stem Cell and Alters the Phenotype of Highly Metastatic Osteosarcoma Cells
3D Implicit Transporter for Temporally Consistent Keypoint Discovery
Keypoint-based representation has proven advantageous in various visual and
robotic tasks. However, the existing 2D and 3D methods for detecting keypoints
mainly rely on geometric consistency to achieve spatial alignment, neglecting
temporal consistency. To address this issue, the Transporter method was
introduced for 2D data, which reconstructs the target frame from the source
frame to incorporate both spatial and temporal information. However, the direct
application of the Transporter to 3D point clouds is infeasible due to their
structural differences from 2D images. Thus, we propose the first 3D version of
the Transporter, which leverages hybrid 3D representation, cross attention, and
implicit reconstruction. We apply this new learning system on 3D articulated
objects and nonrigid animals (humans and rodents) and show that learned
keypoints are spatio-temporally consistent. Additionally, we propose a
closed-loop control strategy that utilizes the learned keypoints for 3D object
manipulation and demonstrate its superior performance. Codes are available at
https://github.com/zhongcl-thu/3D-Implicit-Transporter.Comment: ICCV2023 oral pape
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