Degradation of Minocycline by the Adsorption–Catalysis Multifunctional PVDF–PVP–TiO2 Membrane: Degradation Kinetics, Photocatalytic Efficiency, and Toxicity of Products

The photocatalytic degradation of minocycline was studied by using polyvinylidene fluoride–polyvinylpyrrolidone–TiO2 (PVDF–PVP–TiO2) fiber mats prepared by an electrospinning technology. The influences of the TiO2 dosage, minocycline concentrations, inorganic anions, pH values, and dissolved organic matter (DOM) concentrations on the degradation kinetics were investigated. A mass of 97% minocycline was degraded in 45 min at 5% TiO2 dosage. The corresponding decomposition rate constant was 0.069 min−1. The inorganic anions affected the minocycline decomposition in the order of HCO3− > Cl− > SO42− > NO3−, which was confirmed by the results of electron spin resonance (ESR) spectra. The lowest electrical energy per order (EEO) was 6.5 Wh/L. Over five cycles, there was no change in the photocatalytic performance of the degrading minocycline. Those investigations suggested that effective degradation of minocycline could be reached in the PVDF–PVP–TiO2 fiber mats with a low energy consumption, good separation and, good recovery. Three photocatalytic decomposition pathways of minocycline were proposed: (i) hydroxyl substitution of the acylamino group; (ii) hydroxyl substitution of the amide group, and (iii) a cleavage of the methyl groups and further oxidation of the amino group by OH. Potential risks caused by TP159 and TP99 should not be ignored, while the TP90 are nontoxic. Tests indicated that the toxicity of the photocatalytic process may be persistent if minocycline and its products were not mineralized completely.

Symmetry, Combinatorics, Artificial Intelligence, Music and Spectroscopy

Symmetry forms the foundation of combinatorial theories and algorithms of enumeration such as Möbius inversion, Euler totient functions, and the celebrated Pólya’s theory of enumeration under the symmetric group action. As machine learning and artificial intelligence techniques play increasingly important roles in the machine perception of music to image processing that are central to many disciplines, combinatorics, graph theory, and symmetry act as powerful bridges to the developments of algorithms for such varied applications. In this review, we bring together the confluence of music theory and spectroscopy as two primary disciplines to outline several interconnections of combinatorial and symmetry techniques in the development of algorithms for machine generation of musical patterns of the east and west and a variety of spectroscopic signatures of molecules. Combinatorial techniques in conjunction with group theory can be harnessed to generate the musical scales, intensity patterns in ESR spectra, multiple quantum NMR spectra, nuclear spin statistics of both fermions and bosons, colorings of hyperplanes of hypercubes, enumeration of chiral isomers, and vibrational modes of complex systems including supergiant fullerenes, as exemplified by our work on the golden fullerene C150,000. Combinatorial techniques are shown to yield algorithms for the enumeration and construction of musical chords and scales called ragas in music theory, as we exemplify by the machine construction of ragas and machine perception of musical patterns. We also outline the applications of Hadamard matrices and magic squares in the development of algorithms for the generation of balanced-pitch chords. Machine perception of musical, spectroscopic, and symmetry patterns are considered.

Spectroscopic Elucidation of Some Complexes of Vanillin Semicarbazone

3-Phenyl-4-methoxybenzaldehyde undergoes condensation with semicarbazide hydrochloride to form a Schiff-base i.e. 3-phenyl-4-methoxybenzaldehyde semicarbazone (abbreviated as MBS). It undergoes complexation with Vanadium(II), Manganese(II), and Copper(II). The comparison of FTIR-spectra of complexes with that of free ligand helps ascertain the coordination points of ligand through the nitrogen of –CH=N– group and oxygen of group. The axial ligands have been varied by chloride, acetate and nitrate ions. The UV/Visible and ESR spectra of complexes predicts their tetragonally distorted octahedral (D4h) symmetry. The tetragonal distortion parameter (Dt) is observed maximum for chloride while it is minimum for nitrate along z-axis. Both vanillin and semicarbazide are established biologically active compounds and hence their biological activities may be enhanced by their complexation and than a versatile field may be developed for further exploration.

Dicopper(II)-EDTA Chelate as a Bicephalic Receptor Model for a Synthetic Adenine Nucleoside

In the extensive field of metal ions, their interactions with nucleic acids, and their constituents, the main aim of this work is to develop a metal chelate suitable to recognize two molecules of an adenine nucleoside. For this purpose, the dinuclear chelate Cu2 (µ-EDTA) (ethylenediaminetetraacetate(4-) ion (EDTA)) is chosen as a bicephalic receptor model for N9-(2-hydroxyethyl)adenine (9heade). A one-pot synthesis is reported to obtain the compound [Cu2(µ2-EDTA)(9heade)2(H2O)4]·3H2O, which has been characterized by single-crystal X-ray diffraction and various spectral, thermal, and magnetic methods. The complex unit is a centro-symmetric molecule, where each Cu (II) center is chelated by a half-EDTA, and is further surrounded by an N7-dentate 9heade nucleoside and two non-equivalent trans-O-aqua molecules. The metal chelate-nucleoside molecular recognition is referred to as an efficient cooperation between the Cu-N7(9heade) coordination bond and a (9heade)N6-H···O(carboxyl, EDTA) interligand interaction. Theoretical calculations are also made to account for the relevance of this interaction. The extreme weakness with which each water molecule binds to the metal center disturbs the thermal stability and the infrared (FT-IR) and electron spin resonance (ESR) spectra of the compound.

H-Bonds, π-Stacking and (Water)O-H/π Interactions in (µ4-EDTA)Bis(Imidazole) Dicopper(II) Dihydrate

We synthesized and studied the polymeric compound {[Cu2(µ4-EDTA)(Him)2] 2H2O}n (1). The single-crystal structure is reported along with an in depth characterization of its thermal stability (TGA), spectral properties (FT-IR, Vis-UV and RSE), and magnetic behavior. The crystal consists of infinite 2D-networks built by centrosymmetric dinuclear motifs, constructed by means of a bridging anti,syn-carboxylate group from each asymmetric unit. Each layer guides Him ligands toward their external faces. They are connected by intermolecular (Him)N-H···O(carboxylate) bonds and antiparallel π–π stacking between symmetry related pairs of Him ligands, and then pillared in a 3D-network with parallel channels, where disordered water molecules are guested. About half of the labile water is lost from these channels over a wide temperature range (r.t. to 210 °C) before the other one, most strongly retained by the cooperating action of (water)O1-H(1A)···O(carboxylate) and (water) O1-H(1B)···π(Him) interactions. The latter is lost when organic ligands start to burn. ESR spectra and magnetic measurements indicated that symmetry related Cu(II) centers connected by the bridging carboxylate groups behave magnetically not equivalently, enabling an exchange interaction larger than their individual Zeeman energies.

The Influence of Vanadium Ions in Spectral Properties of ZnO–Sb2O3–B2O3 glasses

Spectroscopic investigations of V2O5 doped ZnO–Sb2O3–B2O3glass system was prepared by melt-quenching technique. ZnO–Sb2O3–B2O3 glasses containing varying concentrations of V2O5 ranging from 0.1 to 1.0 mol% were prepared, here spectroscopic studies such as Optical absorption, IR and ESR spectra have been carried out as a function of vanadium ion concentration. The optical absorption spectrum of glasses has exhibited two broad absorption bands corresponding to 2B2→2B1 and 2B2→2E transitions of VO2+ ions. The appearances of vibration bands in IR spectra are characteristic for B-O-B and V-O-V linkages, showing the network former role of V2O5. Vanadium ions are believed to be present in two possible valence states, namely V4+and V5+. Here with increasing presence of V2 O5 in the glass network, vanadium ions mostly exist in V4+state and occupy modifying positions. Such increase obviously suggests most structural disorder in the network as the concentration of V2 O5 is increased.

ESR and magnetic studies of nickel ions doped P2O5–ZnO–Na2O glassy system

We prepared 42P2O5–40ZnO–(18-x)Na2O–(x)NiO glasses doped with xNiO where 1 ≤ x ≤ 6 mol.%. The optical absorption indicates that the nickel ions exist in both sites tetrahedral and octahedral as the concentration of NiO is increased. This investigation has provided the increasing degree of disorder in the glass network at higher concentrations of NiO. The magnetic characteristics investigated by two techniques electron spin resonance (ESR) spectra and magnetic properties using vibrating sample magnetometer (VSM) at room temperature. The ESR spectra exhibit resonance signal without hyperfine interaction of all the investigated glass samples. It is found that Ni2+ ions were in octahedral sites and it has 3A2g as ground state. The spin-Hamiltonian parameters are evaluated from the ESR spectra and we found a variation of and with different nickel concentration. Interesting results are found for the number of Ni2+ ions participating in resonance (N) and paramagnetic susceptibility (χ). The magnetic properties were performed at room temperature under an applied field of 20 kOe and the hysteresis loops of the powders were extracted for all the considered samples.

Features of charge transport in polymer composites polymethylmethacrylate - polyaniline

The influence of polymer matrix of polymethyl methacrylate (PMMA) on the specific conductivity, percolation threshold, energy of activation of charge transport in polymer composites PMMA − polyaniline (PAN) was studied. Concentration dependence of the electrical conductivity of composites reveals percolation behavior with the low value of percolation threshold within 2 % content of polyaniline. It is found that in the polymer composites PMMA - PAN the specific conductivity increases by more than 8−9 orders of magnitude compared to the original matrix. On the base of temperature dependence of the specific conductivity of the obtained composites, it is concluded that PMMA polymer matrix does not change the semiconductor nature of PAN conductivity in the composite but effects on the activation parameters of the charge transport. From ESR spectra, it found that the presence of a polymeric matrix causes significant delocalization of the charge along the macrochains of the dielectric polymeric matrix.

Structure and Physicochemical Properties of Water Treated under Nitrogen with Low-Temperature Glow Plasma

Water treated with low-temperature, low-pressure glow plasma (GP) in contact with air stimulates various microorganisms, the growth of various plants and provides healthy breeding of various animals. In this paper, we present water treated with GP under oxygen-free nitrogen. It is potentially suitable for breeding anaerobic microorganisms, and increasing the crops of plants utilizing atmospheric nitrogen. Deionized water saturated with oxygen-free nitrogen was treated for 5 to 90 min with low-temperature glow plasma (GP). That operation produced nitrogen in various exited states depending on the treatment time. These excited nitrogen molecules built aqueous clathrates around them. The number and structure of those clathrates depended on the time of the treatment with GP. In terms of mass, density, pH, conductivity, surface tension, Ultraviolet-Visible (UV-VIS), Fourier Transformation Infrared (FTIR), Raman and Electron Spin Resonance (ESR) spectra as well as Differential Scanning Calorimetry (DSC), the macrostructure of water saturated with nitrogen treated with GP strongly depended on the treatment time. Based on the entropy criterion, the macrostructure formed on 30 and 5 min treatment was the most and least organized, respectively.