Synthesis and physico-chemical studies of a novel noncentrosymmetric heptacoordinated cadmium(II) compound containing a tripodal amine, CdCl2[N(C2H6N)3]2

A new noncentrosymmetric Cd(II) complex with thetripodal amine tris(2-aminoethyl)amine, CdCl2[N(C2H6N)3]2, has been prepared and characterized by single crystal X-ray diffraction, solid state NMR and IR spectroscopies. In the complex, the Cd(II) ion is surrounded by sevennitrogen atoms. The organic molecule acts as both a tri-and a tetradentate ligand. The cationic complexes are linked to each other forming layers parallel to the (a, b)plan. The Cl- counter ions occupy the cavities created inside these layers. The 13C CP-MAS NMR spectra are in agreement with the X-ray structure. DFT calculations allow the attribution of the carbon peaks to the differentatoms.The vibrational absorption bands were identified by infrared spectroscopy and DFT calculations allowed their attributions

Cathodoluminescence investigations of GaAs thin layers

AbstractIn this work, we report the theoretical results of cathodoluminescence (CL) for GaAs layer. The simulation of the CL excitation and intensity is developed using 2-D model based on the electron beam energy dissipation and taking into account the effects of carrier diffusion, internal absorption and the recombination process in the semiconductors.We have investigated the influence of the electron beam conditions (energy, current and beam diameter) and some physical parameters (absorption coefficient, gap energy) on the CL intensity. Results allow us particularly to predict the intensity evolution and shift of CL peak emitted near the fundamental energy gap as a function of the electron beam current and energy. A comparative study between simulated and experimental CL spectra at low temperature is realized

Degradation of human kininogens with the release of kinin peptides by extracellular proteinases of Candida spp.

The secretion of proteolytic enzymes by pathogenic microorganisms is one of the most successful strategies used by pathogens to colonize and infect the host organism. The extracellular microbial proteinases can seriously deregulate the homeostatic proteolytic cascades of the host, including the kinin-forming system, repeatedly reported to he activated during bacterial infection. The current study assigns a kinin-releasing activity to secreted proteinases of Candida spp. yeasts, the major fungal pathogens of humans. Of several Candida species studied, C. parapsilosis and C. albicans in their invasive filamentous forms are shown to produce proteinases which most effectively degrade proteinaceous kinin precursors, the kininogens. These enzymes, classified as aspartyl proteinases, have the highest kininogen-degrading activity at low pH (approx. 3.5), but the associated production of bradykinin-related peptides from a small fraction of kininogen molecules is optimal at neutral pH (6.5). The peptides effectively interact with cellular B2-type kinin receptors. Moreover, kinin-related peptides capable of interacting with inflammation-induced B1-type receptors are also formed, but with a reversed pH dependence. The presented variability of the potential extracellular kinin production by secreted aspartyl proteinases of Candida spp. is consistent with the known adaptability of these opportunistic pathogens to different niches in the host organism

Synthesis, crystal structure and spectroscopic characterization of a new organic bismuthate (III) [C9H28N4][Bi2Cl10].H2O

The chemical preparation, crystal structure and spectroscopic characterization of [C9H28N4][Bi2Cl10].H2O have been reported. This compound crystallizes in the monoclinic system in space group P21/c and cell parameters a = 12.2385 (6), b = 17.3062 (7), c = 13.0772 (6) Å, β = 104.475 (5)°, Z = 4 and V = 2681.9 (2) Å3. Its crystal structure has been determined and refined to R = 0.049, using 5848 independent reflections. The atomic arrangement can be described by an alternation of organic and inorganic layers. The inorganic layer built up of [Bi2Cl10]4– bioctahedra arranged in sandwich between the organic layer. The organic groups are interconnected by the water molecules through N-H…O(W) hydrogen bonds to form infinite zig-zag chains spreading along the b-axis. These Chains are themselves interconnected by means of the N–H…Cl hydrogen bonds originating from [Bi2Cl10]4– anions, to form a three-dimensional network. Intermolecular Cl…Cl interactions between adjacent dimeric [Bi2Cl10]4– anions have been observed. The compound was also characterized by FT-IR and Raman spectrscopies

Bis(2-amino-6-methyl­pyrimidin-1-ium-4-olate-κ2 N 3,O)bis­(nitrato-κ2 O,O′)cadmium(II)

In the title compound, [Cd(NO3)2(C5H7N3O)2], the CdII atom is eight-coordinated by two amine N atoms and two O atoms from two zwitterionic, biodentate 2-amino-6-methyl­pyrimidin-1-ium-4-olate ligands and by four O atoms from two nitrate groups. Intra­molecular N—H⋯O hydrogen bonds occur. The crystal packing is stabilized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds, two of which are bifurcated, between the nitrate anions and the organic groups

Versatile anti-infective properties of pyrido- and dihydropyrido[2,3-d]pyrimidine-based compounds

A series of 1H-indeno[2',1':5,6]dihydropyrido[2,3-d]pyrimidine and 1H-indeno[2',1':5,6]pyrido[2,3-d]pyrimidine derivatives was prepared and screened for antiparasitic and viral RNase H inhibitory activity. Several compounds showed considerable activity against Toxoplasma gondii parasites and Leishmania major amastigotes, which warrants further investigation. Based on the structural similarities of certain derivatives with common viral RNase H inhibitors, a HIV-1 RNase H assay was used to study the RNase H inhibition by selected test compounds. Docking of active derivatives into the active site of the HIV-1 RNase H enzyme was carried out. The new compound 2a, inactive in the antiparasitic tests, showed distinct HIV-1 RNase H inhibition. Thus, ring substitution determines antiparasitic or HIV-1 RNase H inhibitory activity of this promising compound class

Bis[2-amino-6-methyl­pyrimidin-4(1H)-one-κ2 N 3,O]dichloridocadmium(II)

In the title compound, [CdCl2(C5H7N3O)2], the CdII atom is six-coordinated by two heterocyclic N atoms [Cd—N = 2.261 (2) and 2.286 (2) Å] and two O atoms [Cd—O = 2.624 (2) and 2.692 (2) Å] from two bidentate chelate 2-amino-6-methyl­pyrimidin-4(1H)-one ligands and two chloride ions [Cd—Cl = 2.4674 (6) and 2.4893 (7) Å]. The crystal packing is characterized by an open-framework architecture with the crystal packing stabilized by inter­molecular N—H⋯Cl and N—H⋯O hydrogen bonds

A New Zn(II) Metal Hybrid Material of 5-Nitrobenzimidazolium Organic Cation (C7H6N3O2)2[ZnCl4]: Elaboration, Structure, Hirshfeld Surface, Spectroscopic, Molecular Docking Analysis, Electric and Dielectric Properties

The slow solvent evaporation approach was used to create a single crystal of (CHNO)[ZnCl] at room temperature. Our compound has been investigated by single-crystal XRD which declares that the complex crystallizes in the monoclinic crystallographic system with the P2/c as a space group. The molecular arrangement of the compound can be described by slightly distorted tetrahedral ZnCl anionic entities and 5-nitrobenzimidazolium as cations, linked together by different non-covalent interaction types (H-bonds, Cl…Cl, π…π and C–H…π). Hirshfeld’s surface study allows us to identify that the dominant contacts in the crystal building are H…Cl/Cl…H contacts (37.3%). FT-IR method was used to identify the different groups in (CHNO)[ZnCl]. Furthermore, impedance spectroscopy analysis in 393 ≤ T ≤ 438 K shows that the temperature dependence of DC conductivity follows Arrhenius’ law. The frequency–temperature dependence of AC conductivity for the studied sample shows one region (E = 2.75 eV). In order to determine modes of interactions of compound with double stranded DNA, molecular docking simulations were performed at molecular level

Metasurface-Inspired Flexible Wearable MIMO Antenna Array for Wireless Body Area Network Applications and Biomedical Telemetry Devices

This article presents a sub-6GHz ISM-band flexible wearable MIMO antenna array for wireless body area networks (WBANs) and biomedical telemetry devices. The array is based on metasurface inspired technology. The antenna array consists of 2×2 matrix of triangular-shaped radiation elements that were realized on 0.8 mm thick Rogers RT/duroid 5880 substrate. Radiation characteristics of the array are enhanced by isolating the surface current interaction between the individual radiators in the array. This is achieved by inserting an electromagnetic bandgap (EBG) decoupling structure between the radiating elements. The radiating elements were transformed into a metasurface by etching sub-wavelength slots inside them. The periodic arrangement of slots acts like resonant scatterers that manipulate the electromagnetic response of the surface. Results confirm that by employing the decoupling structure and sub-wavelength slots the isolation between the radiators is significantly improved (>34.8 dB). Moreover, there is an improvement in the array’s fractional bandwidth, gain and the radiation efficiency. The optimized array design for operation over 5.0-6.6 GHz has an average gain and efficiency of 10 dBi and 83%, respectively. Results show that the array’s performance is not greatly affected by a certain amount of bending. In fact, the antenna maintains a gain between 8.65-10.5 dBi and the efficiency between 77-83%. The proposed MIMO antenna array is relatively compact, can be easily fabricated on one side of a dielectric material, allows easy integration with RF circuitry, is robust, and maintains its characteristics with some bending. These features make it suitable for various wearable applications and biomedical telemetry devices