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Abstract Achieving highly sensitive electrochemical detection of nitrite for the control of nitrite contamination is a constant challenge, therefore, exploring hierarchical nanostructured materials for electrochemical detection with high activity is a vital importance. In the present study, we prepared the highly ordered MOFs-derived α-Fe 2 O 3 /CNTs hybrids through in - situ insertion of carbon nanotubes into MIL-101 (Fe) and their subsequent calcination for electrochemical detection of nitrite. MOFs-derived α-Fe 2 O 3 polyhedrons are attached on the surface of CNTs tightly, forming hierarchical hybrids with interconnected building blocks. The in - situ insertion of CNTs in the novel hybrids shortens the electron-transfer distance between the α-Fe 2 O 3 and CNTs, which makes α-Fe 2 O 3 become highly active for oxidation of nitrite. The prepared sensor demonstrated excellent performances of nitrite detection with the limit of detection (LOD) as low as 0.15 μM, the high sensitivity of 334 μA mM−1 cm−2 and the wide linear range from 0.5 μM to 4000 μM. What's more, the prepared sensor displayed the prominent reproducibility and superior stability with excellent anti-interference ability, and then was successfully applied for the detection of nitrite in Tap water and Pond water. Graphical abstract Highly sensitive electrochemical detection of nitrite based on CNTs-inserted MOFs-derived α-Fe 2 O 3 polyhedrons. Image 1 Highlights • Prepared MOFs-derived α-Fe 2 O 3 /CNTs hybrids through self-assembly and calcination. • In - situ insertion shortens electron-transfer distance between α-Fe 2 O 3 and CNTs. • α-Fe 2 O 3 becomes highly active for oxidation of nitrite in the hybrids. • Electrochemical sensor displays highly sensitive detection of nitrite. [ABSTRACT FROM AUTHOR]

We consider distributionally robust two-stage stochastic convex programming problems, in which the recourse problem is linear. Other than analyzing these new models case by case for different ambiguity sets, we adopt a unified form of ambiguity sets proposed by Wiesemann, Kuhn and Sim, and extend their analysis from a single stochastic constraint to the two-stage stochastic programming setting. It is shown that under a standard set of regularity conditions, this class of problems can be converted to a conic optimization problem. Numerical results are presented to show the efficiency of the distributionally robust approach. [ABSTRACT FROM AUTHOR]

To elucidate whether cranial electrotherapy stimulation (CES) improves depression-like behavior of post-stroke depression (PSD) via regulation of glutathione peroxidase 4 (GPX4)-mediated brain-derived neurotrophic factor (BDNF) expression. Middle cerebral artery occlusion (MCAO) and chronic unpredictable mild stress (CUMS) were used to develop a rat PSD model. CES was applied, and RAS-selective lethal 3 (RSL3) was injected into the hippocampus to inhibit GPX4 in PSD rats. The depression behavior was detected by sucrose preference and forced swimming tests. The structure and morphology of the hippocampus were observed and analyzed by histopathological hematoxylin-eosin (HE) staining. The mRNA and protein expressions of GPX4 and BDNF in the hippocampus were detected by qRT-PCR, western blot and immunohistochemical analysis.The degeneration and necrosis of hippocampal neurons, the depression-like behavior were severer and the expression of BDNF in the hippocampus were decreased in PSD rats than those in MCAO and control groups. CES promoted the hippocampal neuron repair, alleviated the depression-like behavior and increased the expression of BDNF in PSD rats. The inhibition of GPX4 by RSL3 exacerbated the depression-like behavior and decreased the expression of BDNF in PSD rats. In addition, we found that RSL3 disrupted the positive effects of CES on the PSD rats. Conclusion: CES improves depression-like behavior of PSD rats through upregulation of GPX4-mediated BDNF expression in the hippocampus. [ABSTRACT FROM AUTHOR]

Aim To investigate the association between plasma visfatin levels and risk of early and advanced colorectal cancer ( CRC). Methods In total, 358 CRC patients and 286 controls were enrolled. According to the T factor of the TNM system. cancer patients were divided into two subgroups: early and advanced cancer. Levels of visfatin, anthropometric and metabolic parameters, which were classified as low, medium, and high, based on the tertile distributions in the control group, were determined. Results The visfatin levels in patients with advanced and early cancer were higher than in controls (least significant difference test, P = 0.004 and 0.013, respectively). The patients in the highest tertile of visfatin concentration presented significantly higher odds for early and advanced CRC, adjusted for potential confounding factors (odds ratio 3.37; 95% CI, 1.93-8.37; P = 0.011; odds ratio 2.38; 95% CI: 1.82-8.35; P = 0.015, respectively). The visfatin level correlated significantly with waist:hip ratio ( P < 0.05 for all) among case and control participants. Plasma visfatin levels in early and advanced CRC yielded a receiver operating characteristic curve area of 72 and 86%, respectively. The optimal sensitivity and specificity were 73% and 57% in discriminating between early CRC and normal controls while they were 76% and 68% in discriminating between advanced CRC and normal controls. Conclusion An increased level of visfatin was a strong risk factor for both early and advanced CRC in Chinese patients. Plasma visfatin levels might be a potential biomarker for CRC detection. [ABSTRACT FROM AUTHOR]

Objectives: To systematically analyze the diagnostic accuracy of Raman spectroscopy system (RAS) in the rapid diagnosis of gastric cancer with histopathology as the reference standard. Methods: We searched a wide range of electronic databases for all published researches that assessed the diagnostic accuracy of RAS to detect gastric carcinoma. Full papers were obtained for potentially eligible studies and evaluated according to predefined criteria. The Quality Assessment of Diagnostic Accuracy Studies checklist was used to assess the quality of included studies. From each study, we extracted information on diagnostic performance of RAS. After exploring heterogeneity, we adopted a random effects model to pool related effect sizes. Results: The initial literature search identified 257 reference articles in which 15 relevant articles with 15 data sets were selected and reviewed. The pooled sensitivity and specificity of RAS in diagnosing gastric cancer were 0.89 (95 % CI 0.84-0.92) and 0.92 (95 % CI 0.88-0.95), respectively. The positive likelihood ratio, the negative likelihood ratio, and the area under the curve were 10 (95 % CI 6.5-15.3), 0.13 (95 % CI 0.08-0.22), and 0.96 (95 % CI 0.94-0.97), respectively. All the pooled estimates, calculated by random and fixed effect models, were similar. There was no evidence of considerable publication bias. Conclusions: RAS is an objective and sensitive optical diagnostic technology for detecting gastric cancer and has advantages of being noninvasive to the body, real-time diagnosis, and ease of use. Consequently, it does deserve to be recommended. [ABSTRACT FROM AUTHOR]

In this paper, FTIR microspectroscopy was used to compare Cortex Eucommiae from Anhui Province (A), Henan Province (B) and Sichuan Province (C) of China. High-resolution spectra were obtained with good reproducibility. From IR spectra, some obvious differences in band frequency could be observed among Cortex Eucommiae A–C. Curve fitting result indicated that polysaccharides’ structures and contents were different among Cortex Eucommiae A–C. To distinguish Cortex Eucommiae from different producing areas, the A1245/A1328 ratio might be an exceptionally practical factor. Additionally, FTIR microspectroscopy could identify Cortex Eucommiae A–C with 89.5% accuracy in combination with hierarchical cluster analysis. The results suggest FTIR microspectroscopy is very easy and efficient for distinguishing Cortex Eucommiae from different areas, and also indicate FTIR microspectroscopy may be practical for TCM research. [ABSTRACT FROM AUTHOR]

• GCM and G-GCM are proposed for solving group square-root Lasso (GSRL) efficiently. Both of them scale well with large problem scale. • The strict descend property and global convergence are proved. • The proposed algorithms can also be used for fast implementation of statistically sound group-sparse regression methods including SPICE/GSPICE and LIKES/BLIKES. A variant for solving Lasso and group Lasso is also provided. Group square-root Lasso (GSRL) is a promising tool for group-sparse regression since the hyperparameter is independent of noise level. Recent works also reveal its connections to some statistically sound and hyperparameter-free methods, e.g., group-sparse iterative covariance-based estimation (GSPICE). However, the non-smoothness of the data-fitting term leads to the difficulty in solving the optimization problem of GSRL, and available solvers usually suffer either slow convergence or restrictions on the dictionary. In this paper, we propose a class of efficient solvers for GSRL in a block coordinate descent manner, including group-wise cyclic minimization (GCM) for group-wise orthonormal dictionary and generalized GCM (G-GCM) for general dictionary. Both strict descent property and global convergence are proved. To cope with signal processing applications, the complex-valued multiple measurement vectors (MMV) case is considered. The proposed algorithm can also be used for the fast implementation of methods with theoretical equivalence to GSRL, e.g., GSPICE. Significant superiority in computational efficiency is verified by simulation results. [ABSTRACT FROM AUTHOR]

The coast–ship bistatic high-frequency surface wave radar (HFSWR) not only has the anti-interference advantages of the coast-based bistatic HFSWR, but also has the advantages of maneuverability and an extended detection area of the shipborne HFSWR. In this paper, theoretical formulas were derived for the coast–ship bistatic radar, including the first-order sea clutter scattering cross-section and the Doppler frequency shift of moving targets. Then, simulation results of the first-order sea clutter spectrum under different operating conditions were given, and the range of broadening of the first-order sea clutter spectrum and its influence on target detection were investigated. The simulation results show the broadening ranges of the right sea clutter spectrum and left sea clutter spectrum were symmetric when the shipborne platform was anchored, whereas they were asymmetric when the shipborne platform was underway. This asymmetry is primarily a function of platform velocity and radar frequency. Based on experimental data of the coast–ship bistatic HFSWR conducted in 2019, the broadening range of the sea clutter and the target frequency shift were analyzed and compared with simulation results based on the same parameter configuration. The agreement of the measured results with the simulation results verifies the theoretical formulas. [ABSTRACT FROM AUTHOR]

In this paper, we are concerned with a homogeneous reaction–diffusion Atkinson oscillator system subject to homogeneous Neumann boundary conditions on a bounded spatial domain. Using the comparison principle and the techniques of invariant rectangle, we prove the existence of the attraction region of the solutions. We thus prove that under certain conditions, the solutions of the PDE system converge to the unique positive equilibrium solutions. We also derive precise conditions such that the system does not have nonconstant positive steady-state solutions. Finally, we use the bifurcation technique to show the existence of Turing patterns. The results provide a clearer understanding of the mechanism of formations of patterns. [ABSTRACT FROM AUTHOR]