Off-grid direction-of-arrival estimation for wideband noncircular sources

Xiaoyu Zhang1,Haihong Tao,Ziye Fang,Jian Xie 한국전자통신연구원 2023 ETRI Journal Vol.45 No.3

Researchers have recently shown an increased interest in estimating the direction-of-arrival (DOA) of wideband noncircular sources, but existing studies have been restricted to subspace-based methods. An off-grid sparse recovery-based algorithm is proposed in this paper to improve the accuracy of existing algorithms in low signal-to-noise ratio situations. The covariance and pseudo covariance matrices can be jointly represented subject to block sparsity constraints by taking advantage of the joint sparsity between signal components and bias. Furthermore, the estimation problem is transformed into a single measurement vector problem utilizing the focused operation, resulting in a significant reduction in computational complexity. The proposed algorithm's error threshold and the Cramer–Rao bound for wideband noncircular DOA estimation are deduced in detail. The proposed algorithm's effectiveness and feasibility are demonstrated by simulation results.

Extraskeletal Ewing Sarcomas in Late Adolescence and Adults: A Study of 37 Patients

Tao, Hai-Tao,Hu, Yi,Wang, Jin-Liang,Cheng, Yao,Zhang, Xin,Wang, Huan,Zhang, Su-Jie Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: Extraskeletal Ewing sarcoma (EES)/primitive neuroectodermal tumours (PNET) are rare soft tissue sarcomas. Prognostic factors and optimal therapy are still unconfirmed. Materials and Methods: We performed a retrospective analysis on patients to explore the clinic characteristics and prognostic factors of this rare disease. A total of 37 patients older than 15 years referred to our institute from Jan., 2002 to Jan., 2012 were reviewed. The characteristics, treatment and outcome were collected and analyzed. Results: The median age was 28 years (range 15-65); the median size of primary tumours was 8.2 cm (range 2-19). Sixteen patients (43%) had metastatic disease at the initial presentation. Wide surgical margins were achieved in 14 cases (38%). Anthracycline or platinum-based chemotherapy was performed on 29 patients (74%). Radiotherapy was delivered in 13 (35%). At a median follow-up visit of 24 months (range 2-81), the media event-free survival (EFS) and overall survival (OS) were 15.8 and 30.2 months, respectively. The 3-year EFS and OS rates were 24% and 43%, respectively. Metastases at presentation and wide surgical margins were significantly associated with OS and EFS. Tumour size was significantly associated with OS but not EFS. There were no significant differences between anthracycline and platinum based chemotherapy regarding EFS and OS. Conclusions: EES/PNET is a malignant tumour with high recurrence and frequent distant metastasis. Multimodality therapy featuring wide surgical margins, aggressive chemotherapy and adjuvant local radiotherapy is necessary for this rare disease. Platinum-based chemotherapy can be used as an adjuvant therapy.

LncRNA-IMAT1 Promotes Invasion of Meningiomas by Suppressing KLF4/hsa-miR22-3p/Snai1 Pathway

Tao Zhang,Yu Ge,Daijun Wang,Qin Liu,Shuchen Sun,Lingyang Hua,Jiaojiao Deng,Shihai Luan,Haixia Cheng,Qing Xie,Ye Gong,Tao Zhang 한국분자세포생물학회 2022 Molecules and cells Vol.45 No.6

Malignant meningiomas often show invasive growth that makes complete tumor resection challenging, and they are more prone to recur after radical resection. Invasive meningioma associated transcript 1 (IMAT1) is a long noncoding RNA located on Homo sapiens chromosome 17 that was identified by our team based on absolute expression differences in invasive and non-invasive meningiomas. Our studies indicated that IMAT1 was highly expressed in invasive meningiomas compared with non-invasive meningiomas. In vitro studies showed that IMAT1 promoted meningioma cell invasion through the inactivation of the Krüppel-like factor 4 (KLF4)/hsa-miR22-3p/Snai1 pathway by acting as a sponge for hsa-miR22-3p, and IMAT1 knockdown effectively restored the tumor suppressive properties of KLF4 by preserving its tumor suppressor pathway. In vivo experiments confirmed that IMAT1 silencing could significantly inhibit the growth of subcutaneous tumors and prolong the survival period of tumor-bearing mice. Our findings demonstrated that the high expression of IMAT1 is the inherent reason for the loss of the tumor suppressive properties of KLF4 during meningioma progression. Therefore, we believe that IMAT1 may be a potential biological marker and treatment target for meningiomas.

Effect of Continuous Stress-annealing on the Structure and Magnetic Properties of Fe72.9Si15.8B6.9Nb3.2Cu1Co0.2 Amorphous Alloy

Wenfeng Zhang,Jianfeng Wang,Cheng Sun,Ting Zhang,Xueying Zhang,Tao Zhang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.10

The induced magnetic anisotropy, domain structure and magnetic properties of nanocrystallized Fe72.9Si15.8B6.9Nb3.2Cu1Co0.2 materials by continuous stress-annealing at 803–903 K under 0–75 MPa were systematically investigated. It was found that the tensile stress applied during annealing is beneficial to reduce the coercivity and core loss by refining the grain size of α-Fe phase. The remanence and permeability for the annealed samples at 853–903 K are negatively correlated with the induced anisotropy, which increases with the applied tensile stress. The stress-annealed samples yield magnetic easy plane perpendicular to the stress axis with an induced anisotropy constant greater than 1200 J/m3. The nanocrystalline cores with a low AC coercivity of 6.0 A/m and low core loss of 16.1 W/kg in combination with a high DC bias capability was successfully fabricated by stress-annealing the amorphous precursor at 878 K under 40 MPa. The current nanocrystalline material has potential for the application as anti-DC transformers in the electronic field.

Distinct Effects of Non-absorbed Agents Rifaximin and Berberine on the Microbiota-Gut-Brain Axis in Dysbiosis-induced Visceral Hypersensitivity in Rats

Jindong Zhang,Cunzheng Zhang,Tao Zhang,Lu Zhang,Liping Duan 대한소화기 기능성질환∙운동학회 2023 Journal of Neurogastroenterology and Motility (JNM Vol.29 No.4

Background/AimsIrritable bowel syndrome (IBS) is accepted as a disorder of gut-brain interactions. Berberine and rifaximin are non-absorbed antibiotics and have been confirmed effective for IBS treatment, but there is still lack of direct comparison of their effects. This study aims to compare the effect of the 2 drugs on the alteration of gut-brain axis caused by gut microbiota from IBS patients. MethodsGerm-free rats received fecal microbiota transplantation from screened IBS patients and healthy controls. After 14 days’ colonization, rats were administrated orally with berberine, rifaximin or vehicle respectively for the next 14 days. The visceral sensitivity was evaluated, fecal microbiota profiled and microbial short chain fatty acids were determined. Immunofluorescence staining and morphological analysis were performed to evaluate microglial activation. ResultsVisceral hypersensitivity induced by IBS–fecal microbiota transplantation was relieved by berberine and rifaximin, and berberine increased sucrose preference rate. Microbial α-diversity were reduced by both drugs. Compared with rifaximin, berberine significantly changed microbial structure and enriched Lachnoclostridium. Furthermore, berberine but not rifaximin significantly increased fecal concentrations of acetate and propionate acids. Berberine restored the morphological alterations of microglia induced by dysbiosis, which may be associated with its effect on the expression of microbial gene pathways involved in peptidoglycan biosynthesis. Rifaximin affected neither the numbers of activated microglial cells nor the microglial morphological alterations. ConclusionsBerberine enriched Lachnoclostridium, reduced the expression of peptidoglycan biosynthesis genes and increased acetate and propionate. The absence of these actions of rifaximin may explain the different effects of the drugs on microbiota-gut-brain axis.

Relationships of uPA and VEGF Expression in Esophageal Cancer and Microvascular Density with Tumorous Invasion and Metastasis

Jiang, Jian-Tao,Zhang, Lan-Fang,Zhou, Bin,Zhang, Shun-Qun,Li, Shao-Min,Zhang, Wei,Zhang, Jin,Qiao, Zhe,Kong, Ran-Ran,Ma, Yue-Feng,Chen, Sheng Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Objective: To investigate uPA and VEGF expression in esophageal cancer and relations with tumorous invasion and metastasis. Methods: Immunohistochemistry was used to detect uPA and VEGF expression in the normal epithelial tissue of esophageal mucosa and cancer tissue and detect CD34 labeled micrangium and analyze the relationships with clinical pathological features and tumor angiogenesis. Results: Positive rates for uPA and VEGF protein expression were significantly greater in esophageal cancer than normal epithelial tissue (P < 0.05), the two being linked (P <0.05). In addition, uPA and VEGF protein expression of the high microvessel density (MVD) group was significantly lower than in the low MVD group (P < 0.05), with relation to clinical pathological staging, differentiation and lymph node metastasis (P < 0.05). Conclusion: In esophageal cancer tissue, uPA and VEGF proteins are overexpressed and promote tumor angiogenesis, indicative of a poor prognosis.

Magnesium isoglycyrrhizinate inhibits L-type Ca2+ channels, Ca2+ transients, and contractility but not hERG K+ channels

Yue Lin,Yuanyuan Zhang,Qiongtao Song,Tao Song,Xue Han,Ying Zhang,Xuan Zhang,Xi Chu,Fenghua Zhang,Li Chu,Jianping Zhang 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.10

To explore the cardiovascular protective effectsof Magnesium isoglycyrrhizinate (MI), especially theunderlying cellular mechanisms related to L-type calciumchannels and myocardial contractility, and to examine theeffects of MI on hERG K? current expressed in HEK293cells. We used the whole-cell patch clamp technique,video-based edge detection and dual excitation fluorescencephotomultiplier systems to explore the effect of MIon L-type Ca2? currents (ICa-L) and cell contraction in ratcardiomyocytes. We also examined the rapidly activatingdelayed rectifier potassium current (IKr) expressed inHEK293 cells using a perforated patch clamp. MI inhibitedICa-L in a dose-dependent manner, with a half-maximalinhibitory concentration (IC50) of 0.22 mg/ml, and themaximal inhibitory effect was 61.10 ± 0.59%. MI at aconcentration of 0.3 mg/ml reduced cell shortening by24.12 ± 3.97% and the peak value of the Ca2? transient by36.54 ± 4.96%. MI had no significant influence on hERGK? channels expressed in HEK293 cells at all testpotentials. MI exerts protective effects on the heart via theinhibition of ICa-L and cell shortening in rat cardiomyocytes. However, MI had no significant influence on IKr;thus, MI may exert cardioprotective effects without causingdrug-induced long QT syndrome.

Faith Commercialization

Tao Zhang 한국콘텐츠학회 2012 ICCC International Digital Design Invitation Exhib Vol.8 No.2

Bayesian algorithm based on auxiliary variables for estimating item response theory models with non-ignorable missing response data

Zhang Jiwei,Zhang Zhaoyuan,Tao Jian 한국통계학회 2021 Journal of the Korean Statistical Society Vol.50 No.4

Missing responses generally exist in educational and psychological assessments. The statistical inference will lead to serious deviation if the missing responses are not properly modeled in the framework of non-ignorable missing mechanism. In this current study, it is studied whether the different missing mechanism (ignorable missing and non-ignorable missing) models are appropriate to analyze the missing response data from the perspective of parameter estimation and model assessment. In addition, a highly effective Bayesian sampling algorithm based on auxiliary variables is used to estimate the complex models. Compared with the traditional marginal likelihood method and other Bayesian algorithms, the advantages of the new algorithm are discussed in detail. Based on the Markov Chain Monte carlo samples from the posterior distributions, the deviance information criterion (DIC) and the logarithm of the pseudomarignal likelihood (LPML) are employed to compare the different missing mechanism models. Four simulation studies are conducted and a detailed analysis of PISA science data is carried out to further illustrate the proposed methodology.

Application of a finite element and boundary element coupling algorithm in pressure response of a fracture-vuggy gas reservoir

Tao Zhang,Peng Chen,Yan Chen 한국자원공학회 2019 Geosystem engineering Vol.22 No.1

In carbonate reservoirs, multiple large-scale caves are controlled by some single wells. The fluid flowing law in the reservoir is complex, and the production performance is unclear, which restricts the highly effective development of these kinds of reservoirs. In this paper, Darcy flow is used to characterize the fluid flow outside the cave, and the Navier–Stokes equation is used to characterize the free flow of the fluid in the cave. Based on the Darcy flow and Navier–Stokes equations, a fluid flow mathematical model is established for carbonate gas reservoirs with multiple large-scale caves. Then, the Beavers–Joseph–Saffman boundary condition, the finite element and boundary element coupling algorithm are proposed for computing the bottom-hole pseudo-pressure. Subsequently, we establish the interpretation graph for a large-scale cave reservoir and analyse the influence of the reservoir parameters on the pseudo-pressure and pseudo-pressure derivative curves. The results showed the following: (i) the larger the radius of the cave, the larger the concave-convex amplitude of the bottom-hole pressure curve. (ii) For the bottom-hole pressure curve, the smaller the distance, the earlier the convex appears and the larger the concave-convex amplitude. The research results can improve the development effects of carbonate reservoirs with large-scale caves.