Symmetrical Derivatives Research Articles

Local convex-and-concave pattern: An effective texture descriptor

Aiming at the defect of local binary pattern (LBP), this paper presents a novel and efficient local second-order derivative descriptor for image texture feature extraction based on local convex-and-concave pattern (LCCP). LCCP encodes local directional second-order derivative feature of texture based on local convex-and-concave characteristic, which can really capture the derivative information of texture than the center symmetric local derivative pattern (CS-LDP) does. The proposed multi-resolution LCCP not only encodes directional derivative information but also constructs spatial relationships in a given local region by bilinear interpolation. Extensions of multi-resolution LCCP based on uniform pattern and weighted pattern have also been discussed. The performance of the proposed LCCP and its extensions are assessed on the biometric recognition and texture classification under different challenges. Each image is divided into several regions from which histogram features are extracted and concatenate into an enhanced feature vector for match. Extensive experiments have validated the effectiveness of LCCP and its extensions.

Linear Photophysics and Femtosecond Nonlinear Spectroscopy of a Star-Shaped Squaraine Derivative with Efficient Two-Photon Absorption

The synthesis, comprehensive linear photophysical and photochemical study, two-photon absorption (2PA) spectrum, ultrafast relaxation kinetics in the excited states, and efficient superluminescence properties of a new symmetrical three-armed star-shaped squaraine derivative (1) are presented. The steady-state spectral parameters of 1 in a number of organic solvents, including fluorescence excitation anisotropy spectra, revealed a weak interaction between the squaraine branches and the effect of symmetry breaking in the ground electronic state. The degenerate 2PA spectrum of 1 was obtained over a broad spectral range with a maximum cross section of ∼8000 GM using the open aperture Z-scan technique. The nature of the fast dynamic processes in the excited electronic states of 1 was investigated by the femtosecond transient absorption pump–probe method, revealing characteristic relaxation times of ∼3–4 ps. The efficient superluminescence emission of 1 was observed in relatively low concentration solution (≈ 2...

Synthesis and systematic evaluation of symmetric sulfonated centrally C[sbnd]C bonded cyanine near-infrared dyes for protein labelling

The most commonly used near-infrared cyanine dyes contain an aryl ether that is not fully stable towards nucleophiles. Replacement of the aryl ether by a more stable carbon-carbon bond can improve the stability. In this work we have synthesized a series of four negatively-charged symmetrical CC bond-containing Cy7 derivatives and compared them to the known dyes indocyanine green (ICG) and IRDye 800CW. The extent of stacking of these CC bond-containing dyes was higher than reported for aryl ether dyes, but stacking could be minimized by altering the surface charge of the molecules and by introducing sulfonate groups. Furthermore, the degree of stacked dye in an antibody-dye conjugate was similar to the degree of stacking of free dye under labeling conditions. In our view, CC bond-containing Cy7 dyes provide a chemical platform, based on which one can improve the photophysical properties and stacking behavior, thereby generating interesting additions to the conjugation toolbox available for e.g. antibodies.

Synthesis and Linear and Nonlinear Photophysical Characterization of Two Symmetrical Pyrene-Terminated Squaraine Derivatives

Two indole-based squaraine dyes, bearing two pyrenyl groups through vinyl or ethynyl linkers, were synthesized with the aim of enhancing the intramolecular charge transfer interaction in addition to improving their optical properties. The absorption and emission properties of these derivatives were determined to gain insight into the intensity of this type of interaction, their aggregation behavior, and for comparison with results obtained through quantum chemical calculations. Both compounds exhibited high photochemical stability, high molar absorptivity, large fluorescence quantum yields, and relatively low tendency of forming excimers in several solvents. Nonlinear spectroscopic studies revealed two-photon absorption (2PA) cross section maxima greater than 10 000 GM (1 GM = 1 × 10–50 cm4 s/photon), which are higher values relative to the indole-based squaraine core. Experimental results were compared with time-dependent DFT calculations. These observations contribute to the study of intramolecular char...

Explicit formula for the Holevo bound for two-parameter qubit-state estimation problem

The main contribution of this paper is to derive an explicit expression for the fundamental precision bound, the Holevo bound, for estimating any two-parameter family of qubit mixed-states in terms of quantum versions of Fisher information. The obtained formula depends solely on the symmetric logarithmic derivative (SLD), the right logarithmic derivative (RLD) Fisher information, and a given weight matrix. This result immediately provides necessary and sufficient conditions for the following two important classes of quantum statistical models; the Holevo bound coincides with the SLD Cramér-Rao bound and it does with the RLD Cramér-Rao bound. One of the important results of this paper is that a general model other than these two special cases exhibits an unexpected property: the structure of the Holevo bound changes smoothly when the weight matrix varies. In particular, it always coincides with the RLD Cramér-Rao bound for a certain choice of the weight matrix. Several examples illustrate these findings.

Synthesis and Evaluation of Certain Symmetrical Schiff Bases as Inhibitors of MDA-MB-241 Human Breast Cancer Cell Proliferation

A series of symmetrical Schiff base derivatives (L1-L7) were designed by a one-pot condensation reaction of various aldehyde/ketone compounds with hydrazine under mild conditions ( room temperature, 3 days), using ether as solvent and acetic acid as catalyst. The target products were characterized and analysed by H-1 and C-13 NMR, FT-IR and liquid chromatography mass spectrometry (LC/MS). Our research focuses on the identification of synthetically chemotherapeutic substances able to inhibit, delay, or reverse the process of carcinogenesis in several stages. The target compounds presenting two regions for SAR evaluation were screened for their activity toward MDA-MB-241 breast cancer cell proliferation for the first time. Compound (1E, 2E)-1,2-bis(1-(3-nitrophenyl)ethylidene) hydrazine (L6) showed significant inhibitory activity (IC50 = 7.08 mu g/mL).

Specific and non-specific interaction effect on the solvatochromism of some symmetric (2-hydroxybenzilydeamino)phenoxy Schiff base derivatives

In this present work, solvatochromic behavior, specific and non-specific solute–solvent interactions and electronic structure of (2-hydroxybenzilydeamino)phenoxy Schiff base derivatives have been investigated by using electronic absorption spectra in solvent media with different polarities. Electronic absorption spectra are observed to exhibit three main electronic transition bands along with the fourth band which comes into existence from specific solute–solvent interactions. Solute–solvent interaction mechanism and solvatochromic behavior of the studied molecules have been analyzed and evaluated by means of four linear solvation energy relationship (LSER) methods such as Kamlet–Taft parameters, Catalan parameters, Marcus optical dielectric function and Dimroth–Reichardt ET solvent parameter. Achieved results indicate that the mechanisms which control the specific and non-specific solute–solvent interactions are considerably effected by the characteristics of substituents and molecule geometry. According to ET solvent parameter, electronic absorption spectra of (2-hydroxybenzilydeamino)phenoxy Schiff base derivatives exhibit positive solvatochromism. Tautomeric structure and excited state intramolecular proton transfer (ESIPT) have been elucidated by means of resonance structure. A 2D solute–solvent interaction model is investigated theoretically. 3D molecular structure, HOMO (the highest occupied molecular orbital), LUMO (the lowest unoccupied molecular orbital), molecular electrostatic potential (MEP) and solvent accessible surface (SAS) are calculated by using the DFT-B3LYP method.

Thiourea Derivatives as Potent Inhibitors of Aluminum Corrosion: Atomic-Level Insight into Adsorption and Inhibition Mechanisms

Suitable corrosion inhibitors are of prime importance in order to prevent degradation of surfaces by oxidizing chemicals. In this work we studied ten symmetrical thiourea derivatives on aluminum and their efficacy in preventing oxidation by hydrochloric acid computationally and experimentally. We carried out DFT calculations of the inhibitors in both tautomer forms adsorbed on an aluminum-terminated α-alumina surface, focusing on the structure and energetics of adsorption as well as electronic properties. Chemisorption is dominated by electron transfer from the inhibitor S atom toward the surface as well as into the first few layers of the solid. We find that the aggregated amount of transferred charge is an important parameter of the system that correlates with the inhibition efficiency as determined with potentiodynamic measurements. The measurements indicate that the thiourea derivatives are cathodic-type inhibitors, which hinder the reduction of protons and thus indirectly the surface oxidation. This ...

Synthesis of symmetrical terphenyl derivatives by PdCl2-catalyzed Suzuki–Miyaura reaction of dibromobenzene using 3-(diphenylphosphino)propanoic acid as a ligand

ABSTRACTA simple and efficient catalytic system for PdCl2 catalyzing the Suzuki–Miyaura reaction of dibromobenzene and arylboronic acid has been developed by using 3-(diphenylphosphino)propanoic acid as a ligand in dimethylsulfoxide at 100 °C. Using this method, a series of symmetrical terphenyl derivatives were obtained with remarkably good yields, up to 93%.

Application of magnetic nanocomposite modified with a thiourea based ligand for the preconcentration and trace detection of silver(I) ions by electrothermal atomic absorption spectrometry

In this study, a novel and simple modified magnetic nanocomposite was investigated for the analysis of trace amount of silver(I). For this purpose, the magnetically activated carbon/γ-Fe2O3 (AC/γ-Fe2O3) nanocomposite was successfully synthesized and modified with a symmetrical thiourea derivative, 4,4′-bis-(3-phenylthiourea)diphenyl methane (BPDM). The different experimental factors affecting the preconcentration and detection of the analyte ions were studied in detail. The effects of foreign ions on the extraction of Ag(I) ions were also investigated. Under the optimum conditions, a sensitive response to Ag(I) within a wide concentration range (0.01–28μgL−1) was achieved. The limit of detection (LOD, 3Sb/m) was 2.3ngL−1. The maximum adsorption capacity of the novel magnetic adsorbent for Ag(I) was found to be 32.6mgg−1. An enrichment factor (EF) of 125 was obtained by the ratio of the highest sample volume for analyte (125mL) and the lowest final eluent volume (1mL). The developed method was successfully applied to monitoring silver in water samples and the certified reference material. The procedure exhibited some advantages, such as simplicity, rapidity, high sensitivity, and low cost. In addition, the mechanism of silver extraction by modified nanocomposite was proposed.

Synthesis of symmetrical terphenyl derivatives by PdCl2-catalyzed Suzuki–Miyaura reaction of dibromobenzene using 3-(diphenylphosphino)propanoic acid as a ligand

ABSTRACTA simple and efficient catalytic system for PdCl2 catalyzing the Suzuki–Miyaura reaction of dibromobenzene and arylboronic acid has been developed by using 3-(diphenylphosphino)propanoic acid as a ligand in dimethylsulfoxide at 100 °C. Using this method, a series of symmetrical terphenyl derivatives were obtained with remarkably good yields, up to 93%.

Mesoporous Manganese Oxide Catalyzed Aerobic Oxidative Coupling of Anilines To Aromatic Azo Compounds.

Herein we introduce an environmentally friendly approach to the synthesis of symmetrical and asymmetrical aromatic azo compounds by using air as the sole oxidant under mild reaction conditions in the presence of cost-effective and reusable mesoporous manganese oxide materials.

О СТОХАСТИЧЕСКИХ УРАВНЕНИЯХ ЛЕОНТЬЕВСКОГО ТИПА С ПЕРЕМЕННЫМИ МАТРИЦАМИ, ЗАДАННЫМИ В ТЕРМИНАХ ТЕКУЩИХ СКОРОСТЕЙ РЕШЕНИЯ

The stochastic Leontief type equations are a particular case of stochastic systems of differential-algebraic type. The paper deals with the study of the system given in terms of current velocities (symmetric derivatives at an average value) of the solution. It should be noted that in a physical meaning the current velocity of stochastic processes is a direct analog of the physical velocity of deterministic process. The authors assume that the matrices of the system under consideration are rectangular time dependants and satisfy the conditions, under which the system is not solvable with respect to the symmetric derivative. In order to investigate the system of equations the authors use an approach based on the transformation of a square matrix to the canonical Jordan form and changing the metric in the space. The theorem on solution existence for stochastic Leontief type equation with current velocities under some additional conditions on its matrices of coefficients and free terms is proved

Antiviral Activity and Molecular Geometry of Some New Symmetrical Tris(aminoalkyl)amine Derivatives.

We report the preparation of new tripodal receptor-type C3- and CS-symmetrical molecules constructed on a tris(2-aminoethyl)amine (TAEA) template. Both the anti-herpes simplex virus type 1 (anti-HSV-1) activity and cytotoxic activity of synthesized receptor-type derivatives were evaluated in order to find a characteristic structural feature for these bioactivities of compounds. Among the compounds of synthesized symmetrical TAEA-related derivatives, compound 13k showed high anti-HSV-1 activity (50% effective concentration (EC50)=16.7 µM) and low cytotoxicity (50% cytotoxic concentration (CC50)=>200 µM). The presence of a hydrogen bond donor proton in the molecule is thought to be an important structural factor for expressing potential anti-HSV-1 activities.

On Existence of Solutions to Stochastic Differential Inclusions with Current Velocities II

Existence of solution theorems are obtained for stochastic differential inclusions given in terms of the so-called current velocities (symmetric mean derivatives, a direct analogs of ordinary velocity of deterministic systems) and quadratic mean derivatives (giving information on the diffusion coefficient) on the flat $n$-dimensional torus. Right-hand sides in both the current velocity part and the quadratic part are set-valued but satisfy some natural conditions, under which they have $\varepsilon$-approximations that point-wise converge to Borel measurable selections of the corresponding set-valued mappings.

Foreground Detection in Surveillance Videos Via a Hybrid Local Texture Based Method

Abstract Foreground detection is a basic but challenging task in computer vision. In this paper, a novel hybrid local texture based method is presented to model the background for complex scenarios and an image segmentation based denoising processing is applied to reduce noise. We combine the uniform pattern of eXtended Center-Symmetric Local Binary Pattern (XCS-LBP) and Center- Symmetric Local Derivative Pattern (CS-LDP) to generate a discriminative feature with shorter histogram. Retaining the strengths of the two textures, it appears to be robust to dynamic scenes, illumination changes and noise. Based on the hybrid feature, we employ an overlapping block based Gaussian Mixture Model (GMM) framework which makes classifying decision in pixel level. Experimental results on two changeling datasets (Wallflower and I2R dataset) clearly justify the performance of proposed method. Besides, we take the foreground masks obtained by proposed method as input to a tracking system showing notable results.

A green chemoselective one-pot protocol for expeditious synthesis of symmetric pyranodipyrimidine derivatives using ZrOCl2.8H2O

A green chemoselective one-pot protocol for expeditious synthesis of symmetric pyranodipyrimidine derivatives using ZrOCl2.8H2O

Theoretical investigation of the broad one-photon absorption line-shape of a flexible symmetric carbazole derivative.

The one-photon absorption spectrum of a carbazole derivative has been studied by employing density functional response theory combined with a mixed quantum/classical (QC) approach to simulate the spectral shape. In a first step of our analysis we employed the vertical gradient (VG) vibronic model to investigate the role of Franck-Condon (FC) profiles of the first ten electronic excited states of the system, underlying most of the range of the experimental spectrum. We then focussed on the first six excited states covering the low-energy region of the spectrum, and investigated the effect of inter-state electronic couplings on the spectral shapes within Herzberg-Teller (HT) theory. Furthermore, in order to introduce the broadening effects due to the two inter-ring torsions, we employed a QC approach, adopting VG vibronic models for high-frequency modes and computing the contribution of the torsions to the spectrum from the distribution of the excitation energies along a two-dimensional relaxed potential energy. Finally, we estimated the solvent inhomogeneous broadening by computing the solvent reorganization energy using a polarizable continuum model. Our calculations allow us to obtain a non-phenomenological description of the low-energy part of the spectrum in semi-quantitative agreement with experiment and to dissect the relative importance of solvent, torsional flexibility, FC vibronic progressions, and inter-state couplings in determining its broad spectral shapes and the modulation of its intensity. Our analysis also clearly highlights that the investigated carbazole represents a big challenge for available methodologies due to the existence of many close-lying excited electronic states coupled by internal low-frequency and high-frequency motions and by solvent fluctuations. The study of their impact on the spectra at the HT level is only approximate and more refined treatments would require a fully quantum-dynamical calculation on the manifold of the coupled states.

Ultrasound-Promoted Synthesis of Symmetrical Bisamides by Reaction between Aromatic Aldehydes and Amides Catalysed by P-Toluenesulfonic Acid

Reaction between aldehydes and amides catalysed by p-toluene sulfonic acid (p-TSA), under ultrasound irradiation and ambient conditions, gives symmetrical bisamide derivatives in excellent yield and in short time.

Effect of UV-irradiation on spectral properties of squaraine dye in diluted solutions

The photosensitive symmetric derivative of quadratic acid (DMSAQ) was been synthesized for the biomedical or analytical purposes. The photochemical properties of the obtained dye were studied by means of absorption spectroscopy in six solvents of different polarity and photoreactivity: chloroform (CHCl3), tetrahydrofuran (THF), ethanol (EtOH), acetonitrile (ACN) dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). Both high-energy radiation (UV–vis) and radiation with lower energy from visible range were applied. It was found that the fastest squaraine dye bleaching takes place in CHCl3 and DMF solutions, which is caused by photosensitivity of these solvents. The most spectacular stabilization effect has been found in DMSO under both visible and ultraviolet radiation. It was shown that the course of photochemical reactions of squaraine in solutions depends on the solvent properties, energy of radiation and mutual solute-solvent interactions. The explanation of squaraine structure and molecular interactions and their impact on photochemistry of studied systems has been supported by theoretical calculations.