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Graphical abstract Highlights • Twenty-six 4-chloro-2 H -thiochromenes were designed and synthesized. • Most compounds showed good antifungal activities against tested fungal strains. • Compound 10e and 10y showed better efficacy than fluconazole against strain 103. Abstract A series of 4-chloro-2 H -thiochromenes featuring nitrogen-containing side chains were designed, synthesized and tested in vitro for their antifungal activities. The results of preliminary antifungal tests showed that most target compounds exhibited good inhibitory activities against Candida albicans , Cryptococcus neoformans , Candida tropicalis. Notably, compounds 10e and 10y showed most potent activity in vitro against a variety of fungal pathogens with low MICs. Meanwhile, low cytotoxicity on mammalian cells has been observed for compounds 10e and 10y in the tested concentrations by the MTT assay. Therefore, the 4-chloro-2 H -thiochromenes with nitrogen-containing groups provide new lead structures in the search for novel antifungal agents. [ABSTRACT FROM AUTHOR]

Conventional methods for signaling analysis are based on linear time invariant (LTI) assumptions. In this paper, we develop a method for efficient and accurate signaling analysis of nonlinear circuits. This method retains the nonlinear simulation as it is instead of linearizing the original nonlinear problem or adopting a simplified nonlinear model, thereby ensuring accuracy. Meanwhile, it does not suffer from the drawbacks of the brute-force nonlinear simulation in computational efficiency. Being a generic method for signaling analysis, the method is applicable to all kinds of nonlinearities as well as the LTI systems. Simulations of realistic industry nonlinear circuits have demonstrated the accuracy and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Excessive acid rainfall associated with emplacement of the Siberian Traps magmatic province is increasingly accepted as a major contributing factor to the end-Permian biosphere crisis. However, direct proxy evidence of terrestrial acidification is so far not available. In this paper, we seek to determine the probability that relative proportions of extractable monophenolic components from soil-derived organic matter in marine sediments provide a molecular proxy for estimating soil acidity. Intermittently low and high ratios of vanillic acid to vanillin detected in latest Permian and earliest Triassic deposits of the southern Alps, Italy, support concepts of pulses of severe acidification (pH <4) during the main phase of the biosphere crisis. [ABSTRACT FROM AUTHOR]

This paper proposes a hierarchical finite-element reduction- recovery method for large-scale transient analysis of highspeed integrated circuits. This method rigorously reduces the matrix of a multilayer system of O(1) to that of a single-cell system of O(N) regardless of the original problem size. More important, the matrix reduction is achieved analytically, and hence the CPU and memory overheads are minimal. In addition, the reduction preserves the sparsity of the original system matrix. As a result, the matrix factorization cost is reduced to O(1) by the proposed method. The CPU cost at each time step scales linearly with the number of unknowns. The method is applicable to any Manhattantype integrated circuit embedded in layered dielectric media. Numerical and experimental results demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, fast algorithms are proposed for an efficient reduction of a 3-D layered system matrix to a 2-D layered one in the framework of the frequency-domain layered finite element method. These algorithms include: 1) an effective preconditioner P that can converge the iterative solution of the volume-unknown- based matrix equation in a few iterations; 2) a fast direct computation of P-1 in linear complexity in both CPU run time and memory consumption; and 3) a fast evaluation of P-1b in linear complexity, with being an arbitrary vector. With these fast algorithms, the volume-unknown-based matrix equation is solved in linear complexity with a small constant in front of the number of unknowns, and hence significantly reducing the complexity of the 3-D to 2-D reduction. The algorithms are rigorous without making any approximation. They apply to any arbitrarily-shaped multilayer structure. Numerical and experimental results are shown to demonstrate the accuracy and efficiency of the proposed algorithms. [ABSTRACT FROM AUTHOR]

Using an H2 matrix as the mathematical framework, we compactly represent a dense system matrix by a reduced set of parameters, thus enabling a significant reduction in computational complexity. The error bound of the H2-matrix-based representation of an electrodynamic problem was derived. We show that exponential convergence with respect to the number of interpolation points can be achieved irrespective of the electric size. In addition, we show that a direct application of H2 -matrix-based techniques to electrodynamic problems would result in a complexity greater than O(N), with N being the matrix size, due to the need of increasing the rank when ascending an inverted tree in order to keep a constant order of accuracy. A rank function was hence developed to maintain the same order of accuracy in a wide range of electric sizes without compromising computational complexity. With this rank function, we demonstrate that given a range of electric sizes which lead to a range of N, the dense system of O(N2) parameters can be compactly stored in O(N) units, and the dense matrix-vector multiplication can be performed in O(N) operations. Moreover, the same order of accuracy can be kept across this range. The method is kernel independent, and hence is suitable for any integral-equation-based formulation. In addition, it is applicable to arbitrary structures. Numerical experiments from small electric sizes to 64 wavelengths have demonstrated the performance of the proposed method. [ABSTRACT FROM AUTHOR]

A time-domain orthogonal finite-element reduction-recovery method is developed to overcome the large problem sizes encountered in the simulation of large-scale integrated-circuit and package problems. In this method, a set of orthogonal prism vector basis functions is developed. Based on this set of bases, an arbitrary 3-D multilayered system such as a combined package and die is reduced to a single-layer system with negligible computational cost. More importantly, the reduced single-layer system is diagonal and, hence, can be solved readily. From the solution of the reduced system, the solution of the other unknowns is recovered in linear complexity. The method entails no theoretical approximation. It applies to any arbitrarily shaped multilayer structure involving inhomogeneous materials or any structure that can be geometrically modeled by triangular prism elements. In addition, it permits nonlinear device modeling and broadband simulation within one run. Numerical and experimental results have demonstrated its accuracy and high capacity in simulating on-chip, package, and die-package interface problems. [ABSTRACT FROM AUTHOR]

A fast-marching time-domain layered finite-element reduction-recovery (LAFE-RR) method is proposed for high-frequency modeling and simulation of large-scale integrated circuits. This method increases the time step of the LAFE-RR method by three orders of magnitude. In addition, it preserves the computational efficiency of the LAFE-RR method, i.e., the matrix reduction is achieved analytically from a three-dimensional layered system to a single-layer one regardless of the original problem size, and the sparsity of the reduced single-layer system matrix is the same as that of the original system matrix. The method applies to any arbitrarily-shaped multilayer structure. Numerical and experimental results are given to demonstrate its validity. [ABSTRACT FROM AUTHOR]

Time-domain layered finite element reduction recovery (LAFE-RR) method was recently developed for large-scale electromagnetic analysis of high-speed integrated circuits (ICs). This method is capable of analytically and rigorously reducing the system matrix of a 3-D multilayer circuit to that of a single-layer one regardless of the original problem size. In addition, the reduced system matrix preserves the sparsity of the original system matrix. In this paper, an efficient algorithm is proposed to recover the volume unknowns in the time-domain LAFE-RR method. This algorithm constitutes a direct solution of the matrix formed by volume unknowns in each layer. This direct solution possesses a linear complexity in both central processing unit (CPU) time and memory consumption. The cost of matrix inversion is negligible. The cost of matrix solution scales linearly with the matrix size. Numerical and experimental results have demonstrated the accuracy and efficiency of the proposed algorithm. [ABSTRACT FROM AUTHOR]

A fast and high-capacity electromagnetic solution, time-domain layered finite element reduction recovery (LAFE-RR) method, is proposed for high-frequency modeling and simulation of large-scale on-chip circuits. This method rigorously reduces the matrix of a multilayer system to that of a single-layer system, regardless of the problem size. More importantly, the matrix reduction is achieved analytically, and hence the CPU and memory overheads are minimal. The recovery of solutions in all other layers involves only forward and backward substitution of matrices of single-layer size. The memory cost is also modest-requiring only the memory needed for the factorization of two sparse matrices of half-layer size. The superior performance applies to any arbitrarily shaped multilayer structure. Numerical and experimental results are presented to demonstrate the accuracy, efficiency, and capacity of the proposed method. [ABSTRACT FROM AUTHOR]

A high-capacity electromagnetic solution, layered finite element method, is proposed for high-frequency modeling of large-scale three-dimensional on-chip circuits. In this method, first, the matrix system of the original 3-D problem is reduced to that of 2-D layers. Second, the matrix system of 2-D layers is further reduced to that of a single layer. Third, an algorithm of logarithmic complexity is proposed to further speed up the analysis. In addition, an excitation and extraction technique is developed to limit the field unknowns needed for the final circuit extraction to a single layer only, as well as keep the right-hand side intact during the matrix reduction process. The entire procedure is numerically rigorous without making any theoretical approximation. The computational complexity only involves solving a single layer irrespective of the original problem size. Hence, the proposed method is equipped with a high capacity to solve large-scale IC problems. The proposed method was used to simulate a set of large-scale interconnect structures that were fabricated on a test chip using conventional Si processing techniques. Excellent agreement with the measured data has been observed from dc to 50 GHz. [ABSTRACT FROM AUTHOR]

An effective algorithm to construct perfectly matched layers (PMLs) for truncating time-domain finite-element meshes used in the simulation of three-dimensional (3-D) open-region electromagnetic scattering and radiation problems is presented. Both total- and scattered-field formulations are described. The proposed algorithm is based on the time-domain finite-element solution of the vector wave equation in an anisotropic and dispersive medium. The algorithm allows for the variation of the PML parameters within each element, which facilitates the efficient use of higher order vector basis functions. The stability of the resultant numerical procedure is analyzed, and it is shown that unconditionally stable schemes can be obtained. Numerical simulations of radiation and scattering problems based on both the zeroth- and higher order vector bases are presented to validate the proposed PML scheme. [ABSTRACT FROM AUTHOR]

This paper presents a general approach for the stability analysis of the time-domain finite-element method (TDFEM) for electromagnetic simulations. Derived from the discrete system analysis, the approach determines the stability by analyzing the root-locus map of a characteristic equation and evaluating the spectral radius of the finite element system matrix. The approach is applicable to the TDFEM simulation involving dispersive media and to various temporal discretization schemes such as the central difference, forward difference, backward difference, and Newmark methods. It is shown that the stability of the TDFEM is determined by the material property and by the temporal and spatial discretization schemes. The proposed approach is applied to a variety of TDFEM schemes, which include: 1) time-domain finite-element modeling of dispersive media; 2) time-domain finite element-boundary integral method; 3) higher order TDFEM; and 4) orthogonal TDFEM. Numerical results demonstrate the validity of the proposed approach for stability analysis. [ABSTRACT FROM AUTHOR]

An algorithm is presented to implement perfectly matched layers (PMLs) for the time-domain finite-element (TDFE) simulation of two-dimensional open-region electromagnetic scattering and radiation problems. The proposed algorithm is based on the TDFE solution of a special vector wave equation similar to the one in an anisotropic and dispersive medium. The impact of the PML on the stability of the resultant TDFE solution is studied for a variety of temporal discretization schemes, and it is shown that the proposed algorithm for implementing PML can support unconditionally stable TDFE schemes. Both the totaland the scattered-field formulations are described, and numerical simulations of radiation and scattering problems are presented to validate the proposed PML algorithm for the mesh truncation of the TDFE solution. [ABSTRACT FROM AUTHOR]

A novel hybrid time-domain finite element-boundary integral method for analyzing three-dimensional (3-D) electromagnetic scattering phenomena is presented. The method couples finite element and boundary integral field representations in a way that results in a sparse system matrix and solutions that are devoid of spurious modes. To accurately represent the unknown fields, the scheme employs higher-order vector basis functions defined on curvilinear tetrahedral elements. To handle problems involving electrically large objects, the multilevel plane-wave time-domain algorithm is used to accelerate the evaluation of the boundary integrals. Numerical results demonstrate the accuracy and versatility of the proposed scheme. [ABSTRACT FROM AUTHOR]

Presents a finite element-boundary integral (FE-BI) scheme for analyzing transient electromagnetic scattering from freestanding inhomogeneous objects. Description of the FE-BI scheme; Evaluation of boundary integrals; Accuracy of the FE-BI scheme.

Background: There are a variety of space-occupying lesions of the kidney, and the benign lesions may be difficult to differentiate from the malignant ones. Therefore, an accurate judgment of the benign and malignant nature of the space-occupying lesions of the kidney is of high importance for the treatment and prognosis of these patients. Objective: To evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) combined with contrast-enhanced computed tomography (CECT) in space-occupying lesions of the kidney. Data and methods: Three hundred and sixty-seven patients with space-occupying lesions of the kidney (378 lesions) were examined by CEUS and CECT, respectively, then, a combined diagnosis was made after the combination of CEUS and CECT by a multidisciplinary team. The diagnoses from the three methods were compared. The pathological results were taken as the gold standard. The sensitivity, specificity, positive and negative predictive values and area under the receiver operating characteristic (ROC) curve were calculated for the three methods. Thus, the diagnostic value of the three methods was assessed. Results: Of the 378 lesions examined, there were 301 malignant lesions and 77 benign lesions. The combined examination revealed 303 malignant lesions, with 9 benign lesions mistakenly diagnosed as malignant ones; thus, the misdiagnosis rate was 11.7%. By using the combined examination, 75 benign lesions were diagnosed, with the missed diagnosis of 7 malignant lesions, so the missed diagnosis rate was 2.3%. The sensitivity, specificity, positive and negative predictive values and area under the ROC curve with the combined examination of CEUS and CECT were 97.67% (0.950-0.989), 88.31% (0.785-0.942), 97.03% (0.942-0.985), 90.67% (0.811-0.958) and 0.930 (0.887-0.973), respectively. As compared with either CEUS or CECT alone, the difference in these indicators was of statistical significance (P,0.05). The combined examination greatly improved the sensitivity, specificity and accuracy of the diagnosis of the space-occupying lesions of the kidney. Conclusion: CEUS and CECT each have advantages and disadvantages in the diagnosis of the space-occupying lesions of the kidney. The two techniques can be used in combination to compensate for the respective defects. More salient benefits can be reaped from the combined examination than from either technique used alone. [ABSTRACT FROM AUTHOR]

Fast algorithms are developed in this work for solving the system matrix resulting from a frequency-domain layered finite element based analysis of integrated circuits. The frequency-domain layered finite element method represents a 3-D layered system by a 2-D layered system, and further by a single-layered one. The reduced system matrix is generally denser than the original sparse matrix. In this paper, we show that 1) the dense matrix-vector multiplication can be performed in linear complexity; in addition, the reduction cost can be bypassed, 2) an effective preconditioner can be developed to converge the iterative solution of the reduced system matrix in a small number of iterations, and 3) the preconditioner can be solved in linear complexity. As a result, the reduced system matrix can be solved efficiently. The algorithms are rigorous without making any approximation. They apply to any arbitrarily-shaped multilayer structure. Numerical results demonstrated the accuracy, effectiveness, and efficiency of the proposed algorithms in analyzing on-chip circuits. [ABSTRACT FROM AUTHOR]

Acute renal infarction (ARI) is an uncommon disease and delayed diagnosis or misdiagnosis often leads to rapid deterioration of the patient. As patients with atrial fibrillation and left atrial myxomas are at risk of developing ARI due to cardiogenic thromboembolism, it is pivotal for clinicians to make a correct diagnosis and start a timely treatment. The present study reported on the case of a 68-year-old man who suffered from ARI secondary to thromboembolism associated with atrial fibrillation and left atrial myxomas. His renal function deteriorated rapidly after the onset of the attack. He was treated with anti-coagulant agents with excellent results. Classical anti-coagulation therapy remains to be the effective and safe treatment of ARI. [ABSTRACT FROM AUTHOR]

The wave-propagation problem in an on-chip interconnect network can be modeled as a generalized eigenvalue problem. For solving such a generalized eigenvalue problem, the computational complexity of Arnoldi iteration is at best O ( k² N), where k is the number of dominant eigenvalues and N is the matrix size. In this paper, we reduce the computational complexity of the Arnoldi iteration for interconnectextraction from O ( k² N) to O(N), thus paving the way for full-wave extraction of very large scale on-chip interconnects, of which a typical value of k is on the order of hundreds of thousands. Numerical and experimental results have demonstrated the accuracy and efficiency of the proposed fast eigenvalue solver. [ABSTRACT FROM AUTHOR]

This paper proposes a linear-time complex-valued eigenvalue solver for solving large-scale on-chip interconnect problems. The fast eigenvalue solution is achieved by eigenvalue clustering, fast system reduction with negligible computational cost, and fast linear-time solution of the reduced system. Numerical and experimental results are presented to demonstrate the accuracy and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]