Comparative study of the alignment method on experimental and simulated chromatographic data

One of the major problems in the signal comparison of chromatographic data is the variability of response caused by instrumental drifts and others instabilities. Measures of quality control and evaluation of conformity are inherently sensitive to shift. It is essential to be able to compare test samples to reference samples in an evolutionary analytical environment by offsetting the inevitable drift. Therefore, prior to any multivariate analysis, the alignment of analytical signals is a compulsory preprocessing step. During recent years, many researchers have taken a greater interest in the study of the alignment. The present paper is an updated review on the alignment algorithms, methods, and improvements used in chromatography. The study is dedicated to one‐dimensional signals. Several of the exposed methods have common theoretical bases and can differ through their optimization methods. The main issue for the operator is to choose the appropriate method according to the type of signals to be processed.     

Synthesis and Single Crystal X-ray Studies of 3-(3,5-Bis(trifluoromethyl)phenyl) Quinoline and 3-(4-Fluoro-3-methylphenyl) Quinoline

The title compounds 3-(3,5-bis(trifluoromethyl)phenyl)quinoline(1) and 3-(4-fluoro-3-methylphenyl)quinoline(2) were synthesized through Suzuki-Miyaura Cross coupling reaction of 3-bromoquinoloine with aryl boronic acids.The title compounds were characterized by single-crystal X-ray diffraction,1H NMR,13C NMR,EI-MS,elemental analysis and IR.The crystals of 3-(3,5-bis(trifluoromethyl)phenyl)quinoline(C17H9F6N,Mr = 341.25) belongs to the monoclinic system,space group P21n,a = 12.3072(13),b = 4.9378(6),c = 24.493(2) ,V = 1473.1(3) 3,Z = 4,Dc = 1.539 Mg m-3,λ = 0.71073 ,μ = 0.144 mm-1,F(000) = 688,the final R = 0.0715 and wR = 0.1873 for 1875 observed reflections with I 2σ(I) and the crystal of 3-(4-fluoro-3-methylphenyl)quinoline(C16H12FN,Mr = 237.27) belongs to the orthorhombic system,space group Pca21,a = 23.794(2),b = 3.9094(3),c = 25.669(2) ,V = 2387.7(4) 3,Z = 8,Dc = 1.320 Mg m-3,λ = 0.71073 ,μ = 0.088 mm-1,F(000) = 992,the final R = 0.0534 and wR = 0.1188 for 2270 observed reflections with I 2σ(I).     

Synthesis,characterization, and biological screening of metal complexes of novel sulfonamide derivatives: Experimental and theoretical analysis of sulfonamide crystal

This study reports the synthesis of sulfonamide-derived Schiff bases as ligands L ¹ and L ² as well as their transition metal complexes [VO(IV), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II)]. The Schiff bases (4-{E-[(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzene-1-sulfonamide ( L ¹ ) and 4-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}-N-(5-methyl-1,2-oxazol-3-yl)benzene-1-sulfonamide ( L ² ) were synthesized by the condensation reaction of 4-aminobenzene-1-sulfonamide and 4-amino-N-(3-methyl-2,3-dihydro-1,2-oxazol-5-yl)benzene-1-sulfonamide with 2-hydroxy-3-methoxybenzaldehyde in an equimolar ratio. Sulfonamide core ligands behaved as bidentate ligands and coordinated with transition metals via nitrogen of azomethine and the oxygen of the hydroxyl group. Ligand L ¹ was recovered in its crystalline form and was analyzed by single-crystal X-ray diffraction technique which held monoclinic crystal system with space group (P2₁/c). The structures of the ligands L ¹ and L ² and their transition metal complexes were established by their physical (melting point, color, yields, solubility, magnetic susceptibility, and conductance measurements), spectral (UV–visible [UV–Vis], Fourier transform infrared spectroscopy, ¹H NMR, ¹³C NMR, and mass analysis), and analytical (CHN analysis) techniques. Furthermore, computational analysis (vibrational bands, frontier molecular orbitals (FMOs), and natural bonding orbitals [NBOs]) were performed for ligands through density functional theory utilizing B3LYP/6-311+G(d,p) level and UV–Vis analysis was carried out by time-dependent density functional theory. Theoretical spectroscopic data were in line with the experimental spectroscopic data. NBO analysis confirmed the extraordinary stability of the ligands in their conjugative interactions. Global reactivity parameters computed from the FMO energies indicated the ligands were bioactive by nature. These procedures ensured the charge transfer phenomenon for the ligands and reasonable relevance was established with experimental results. The synthesized compounds were screened for antimicrobial activities against bacterial (Streptococcus aureus, Bacillus subtilis, Eshcheria coli, and Klebsiella pneomoniae) species and fungal (Aspergillus niger and Aspergillus flavous) strains. A further assay was designed for screening of their antioxidant activities (2,2-diphenyl-1-picrylhydrazine radical scavenging activity, total phenolic contents, and total iron reducing power) and enzyme inhibition properties (amylase, protease, acetylcholinesterase, and butyrylcholinesterase). The substantial results of these activities proved the ligands and their transition metal complexes to be bioactive in their nature.     

A novel bit permutation-based image encryption algorithm

Nonlinear Dynamics - In recent years, substantial work has been done for developing image encryption algorithms. Image encryption requires handling of large data, which needs computationally...     

A microwave-assisted and heteropolyacids-catalysed cyclocondensation reaction for the synthesis of 4(3H)-quinazolinones

We have investigated a microwave-assisted synthesis of 4(3H)-quinazolinones by condensation of anthranilic acid, orthoesters (or formic acid) and substituted anilines,using Keggin-type heteropolyacids (H(3)PW(12)O(40).13H(2)O, H(4)SiW(12)O(40).13H(2)O,H(4)SiMo(12)O(40).13H(2)O or H(3)PMo(12)O(40).13H(2)O) as catalysts. We found that the the use of H(3)PW(12)O(40).13H(2)O acid coupled to microwave irradiation allows a solvent-free, rapid (approximately 13min) and high-yielding reaction.     

A new benzofuranic acid from the leaves of Rhus alata

From leaves of Rhus alata, one new benzofuranic acid named [(2E)-3-(4-hydroxy-5,7-dimethyl- benzo[3,4-b] furan-6-yloxy)-prop-2-enoic acid has been isolated together with eight known compounds: dimethyl ester of terephthalic acid, beta-amyrin, friedelin, lupeol, beta-sitosterol, oleanolic acid, taraxerone and ethyl gallate. Structural elucidations were done on the basis of chemical and physical data (IR, UV, 1H-NMR, 13C-NMR and MS spectra).     

Realization of Holographic Entanglement Temperature for a Nearly-AdS Boundary

Computing the holographic entanglement entropy proposed by Ryu-Takayanagi shows that thermal energy near boundary region in AdS₃ gain maximum of the temperature. The absolute maxima of temperature is \(T^{Max}_{E}= \frac {4G_{3} \epsilon _{\infty }}{l}\). By simple physical investigations it has become possible to predict a phase transition of first order at critical temperature T_c ≤ T_E. As they predict a tail or root towards which the AdS space ultimately tend, the boundary is considered thermalized. The Phase transitions of this form have received striking theoretical and experimental verifications so far.     

Synthesis of ciprofloxacin-based compounds: A review

Ciprofloxacin is a broad-spectrum antibiotic that plays an important role in inhibiting the growth of both Gram-positive and Gram-negative bacteria. Medicinal chemists are extensively involved in the synthesis of novel ciprofloxacin derivatives, in search of new ciprofloxacin-based drugs with enhanced activity. This review article summarizes the major synthetic approaches involved in the synthesis of ciprofloxacin-based molecules.     

Quercetin-Iron Complex: Synthesis,Characterization, Antioxidant,DNA Binding,DNA Cleavage,and Antibacterial Activity Studies

Quercetin-iron (II) complex was synthesized and characterized by elemental analysis, ultraviolet-visible spectrophotometry, fourier transform infrared spectroscopy, mass spectrometry, proton nuclear magnetic resonance spectroscopy, thermogravimetry and differential scanning calorimetry, scanning electron micrography and molar conductivity. The low molar conductivity value investigates the non-electrolyte nature of the complex. The elemental analysis and other physical and spectroscopic methods reveal the 1:2 stoichiometric ratio (metal:ligand) of the complex. Antioxidant study of the quercetin and its metal complex against 2, 2-di-phenyl-1-picryl hydrazyl radical showed that the complex has much more radical scavenging activity than free quercetin. The interaction of quercetin-iron (II) complex with DNA was determined using ultraviolet visible spectra, fluorescence spectra and agarose gel electrophoresis. The results showed that quercetin-iron (II) complex can intercalate moderately with DNA, quench a strong intercalator ethidium bromide and compete for the intercalative binding sites. The complex showed significant cleavage of pBR 322 DNA from supercoiled form to nicked circular form and these cleavage effects were dose-dependent. Moreover, the mechanism of DNA cleavage indicated that it was an oxidative cleavage pathway. These results revealed the potential nuclease activity of complex to cleave DNA. In addition, antibacterial activity of complex on E.coli and S. aureus was also investigated. The results showed that complex has higher antibacterial activity than ligand.     

Analyzing normal proliferating,hypoxic and necrotic regions of T-47D human breast cancer spheroids using Raman spectroscopy

Raman spectroscopy is an advanced chemical analytical technique that has gained significant interest in cancer research, in particular early detection and monitoring of cancer, with added advantages of non-invasive and real-time diagnosis. Recently, studies have shown its sensitivity to monitor chemical changes during cancer progression. This information will lead to identification of chemical markers (molecular fingerprints of chemical composition) that can be used as biological markers. In this study, we used a tumor spheroid model that mimics the characteristics of a non-vascular in vitro tumor model, we used a combination of Raman and multivariate approach to identify chemical changes associated with normal proliferating, hypoxic and necrotic regions of T-47D human breast cancer spheroid model. The results provide evidence that lipids, amide I, III and nucleic acid contents differ significantly in normal, hypoxic and necrotic regions. Principal component analysis loading plots has suggested that normal proliferating region separated with low amide I and high-tryptophan content compared to hypoxic and necrotic regions. These differences observed in three regions might be useful in identification of new spectral markers associated stress faced by each region progressing toward necrosis.