Imaging a moving point source from multi-frequency data measured at one and sparse observation points (part II): near-field case in 3D

In this paper, we introduce a frequency-domain approach to extract information on the trajectory of a moving point source. The method hinges on the analysis of multi-frequency near-field data recorded at one and sparse observation points in three dimensions. The radiating period of the moving point source is supposed to be supported on the real axis and a priori known. In contrast to inverse stationary source problems, one needs to classify observable and non-observable measurement positions. The analogue of these concepts in the far-field regime were firstly proposed in the authors' previous paper (SIAM J. Imag. Sci., 16 (2023): 1535-1571). In this paper we shall derive the observable and non-observable measurement positions for straight and circular motions in $\R^3$. In the near-field case, we verify that the smallest annular region centered at an observable position that contains the trajectory can be imaged for an admissible class of orbit functions. Using the data from sparse observable positions, it is possible to reconstruct the $\Theta$-convex domain of the trajectory. Intensive 3D numerical tests with synthetic data are performed to show effectiveness and feasibility of this new algorithm.Comment: arXiv admin note: substantial text overlap with arXiv:2212.1423

Inverse wave-number-dependent source problems for the Helmholtz equation with partial information on radiating period

This paper addresses a factorization method for imaging the support of a wave-number-dependent source function from multi-frequency data measured at a finite pair of symmetric receivers in opposite directions. The source function is given by the inverse Fourier transform of a compactly supported time-dependent source whose initial moment or terminal moment for radiating is unknown. Using the multi-frequency far-field data at two opposite observation directions, we provide a computational criterion for characterizing the smallest strip containing the support and perpendicular to the directions. A new parameter is incorporated into the design of test functions for indicating the unknown moment. The data from a finite pair of opposite directions can be used to recover the $\Theta$-convex polygon of the support. Uniqueness in recovering the convex hull of the support is obtained as a by-product of our analysis using all observation directions. Similar results are also discussed with the multi-frequency near-field data from a finite pair of observation positions in three dimensions. We further comment on possible extensions to source functions with two disconnected supports. Extensive numerical tests in both two and three dimensions are implemented to show effectiveness and feasibility of the approach. The theoretical framework explored here should be seen as the frequency-domain analysis for inverse source problems in the time domain.Comment: arXiv admin note: text overlap with arXiv:2305.0745

Imaging a moving point source from multi-frequency data measured at one and sparse observation directions (part I): far-field case

We propose a multi-frequency algorithm for imaging the trajectory of a moving point source from one and sparse far-field observation directions in the frequency domain. The starting and terminal time points of the moving source are both supposed to be known. We introduce the concept of observable directions (angles) in the far-field region and derive all observable directions (angles) for straight and circular motions. At an observable direction, it is verified that the smallest trip containing the trajectory and perpendicular to the direction can be imaged, provided the orbit function possesses a certain monotonical property. Without the monotonicity one can only expect to recover a thinner strip. The far-field data measured at sparse observable directions can be used to recover the $\Theta$-convex domain of the trajectory. Both two- and three-dimensional numerical examples are implemented to show effectiveness and feasibility of the approach

Untrained neural network embedded Fourier phase retrieval from few measurements

Fourier phase retrieval (FPR) is a challenging task widely used in various applications. It involves recovering an unknown signal from its Fourier phaseless measurements. FPR with few measurements is important for reducing time and hardware costs, but it suffers from serious ill-posedness. Recently, untrained neural networks have offered new approaches by introducing learned priors to alleviate the ill-posedness without requiring any external data. However, they may not be ideal for reconstructing fine details in images and can be computationally expensive. This paper proposes an untrained neural network (NN) embedded algorithm based on the alternating direction method of multipliers (ADMM) framework to solve FPR with few measurements. Specifically, we use a generative network to represent the image to be recovered, which confines the image to the space defined by the network structure. To improve the ability to represent high-frequency information, total variation (TV) regularization is imposed to facilitate the recovery of local structures in the image. Furthermore, to reduce the computational cost mainly caused by the parameter updates of the untrained NN, we develop an accelerated algorithm that adaptively trades off between explicit and implicit regularization. Experimental results indicate that the proposed algorithm outperforms existing untrained NN-based algorithms with fewer computational resources and even performs competitively against trained NN-based algorithms

Proteomics-based screening and validation of key targets in chronic obstructive pulmonary disease complicated with lung cancer

Objective: To preliminarily predict and verify the biological mechanism and potential core therapeutic targets of chronic obstructive pulmonary disease (COPD)-associated lung cancer （COPD-LC） based on proteomics analysis combined with bioinformatics technology. Methods: Urine samples of COPD, lung cancer patients and healthy people who visited the outpatient clinic of the Fourth Clinical Medical College of Xinjiang Medical University from December 2018 to August 2021 were collected and sequenced by high-throughput sequencing. Differential proteins were screened, protein-protein interaction (PPI) network diagrams were constructed, functional enrichment analysis was carried out to further predict the key targets of COPD-LC, and finally the above molecules were verified in the Gene Expression Omnibus (GEO) database. Results: Proteomics results showed that there were 157 differential proteins in the COPD group compared with the normal control group, including 67 up-regulated proteins and 90 down-regulated proteins. Compared with the normal control group, there were 306 differential proteins in the lung cancer group, including 132 up-regulated and 174 down-regulated proteins. In addition, PPI analysis was performed for the above differential proteins based on the Search Tool for the Retrieval of Interacting Genes (STRING) platform. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes （KEGG） analysis showed that COPD-LC was mainly enriched in extracellular region, lysosomes, extracellular space, amylase activity, protease inhibitor activity, defense/immune protein activity and other aspects. The microarray data of COPD and lung cancer were searched in the GEO database, and GSE8581 and GSE43346 were finally included. A total of 13 605 differential genes were identified in GSE8581 dataset, and 3 403 differential genes were identified in GSE43346 dataset. The degree of overlap between the differential genes in the GSE8581 and GSE43346 datasets was further analyzed, and 4 overlapping proteins were found in the two, including latent TGF-β binding protein (LTBP) 4, N-acetyl-alpha-glucosaminidase (NAGLU), ubiquitin protein ligase E3 component N-recognin (UBR) 4, and DNA damage binding protein 1 and cullin-ring ligase 4 associated factor (DCAF) 5, which were verified in the GEO database finally. Conclusion: This study has initially revealed 4 potential therapeutic targets for COPD-LC, including LTBP4, NAGLU, UBR4 and DCAF5, among which NAGLU, UBR4 and DCAF5 are rarely reported in the research of COPD and lung cancer. The above proteins are significantly low expressed in COPD and lung cancer, and may become significant biomarkers for the diagnosis and treatment of COPD-LC

In-situ growth of nanowire WO2.72 on carbon cloth as a binder-free electrode for flexible asymmetric supercapacitors with high performance

For the first time, WO2.72 nanowires were in-situ grown on carbon cloth by a simple solvothermal reaction. The nanowire WO2.72/carbon cloth (NW WO2.72/CC) electrode showed good electrochemical performance with specific capacitance (C s) reaching up to 398 F g-1 at a current density of 2 A g-1. The capacitance of 240 F g-1 was retained at a high current density of 16 A g-1. To further evaluate the energy storage performance, flexible asymmetric supercapacitors (FASCs) were fabricated using the activated carbon/carbon cloth (AC/CC) as negative electrode and NW WO2.72/CC as positive electrode, respectively. The FASCs delivered a high energy density of 28 Wh kg-1 at a power density of 745 W kg-1 and 13 Wh kg-1 even at a high power density of 22.5 kW kg-1. More impressively, 81% of the specific capacitance of the FASCs was retained after 10,000 cycles, indicating excellent cycle stability. This work indicates the NW WO2.72/CC holds a great potential for application in energy storage devices

Association between novel PLCE1variants identified in published esophageal cancer genome-wide association studies and risk of squamous cell carcinoma of the head and neck

BACKGROUND: Phospholipase C epsilon 1 (PLCE1) (an effector of Ras) belonging to the phospholipase family plays crucial roles in carcinogenesis and progression of several cancers, including squamous cell carcinoma of the head and neck (SCCHN). A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus in genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) that share similar risk factors with SCCHN. Therefore, we investigated the association between potentially functional SNPs in PLCE1 and susceptibility to SCCHN. METHODS: We genotyped three potentially functional SNPs (rs2274223A/G, rs3203713A/G and rs11599672T/G) of PLCE1 in 1,098 SCCHN patients and 1,090 controls matched by age and sex in a non-Hispanic white population. RESULTS: Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (P(trend )= 0.046), particularly for non-oropharyngeal tumors (P(trend )= 0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR = 1.29, 95% CI = 1.01-1.64; AG/GG vs. AA: adjusted OR = 1.30, 95% CI = 1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR = 0.54, 95% CI = 0.34-0.86; TG/GG vs. TT: adjusted OR = 0.76, 95% CI = 0.61-0.95). CONCLUSIONS: Our findings suggest that PLCE1 variants may have an effect on risk of SCCHN associated with tobacco and alcohol exposure, particularly for those tumors arising at non-oropharyngeal sites. These findings, although need to be validated by larger studies, are consistent with those in esophageal and gastric cancers