Influence of rotational barrier of single-molecule electric revolving door on energies,aromaticity and quadrupole moment

We studied the response of rotation of spindle ring on energies, aromaticity and quadrupole moment in single-molecule revolving door (S-MERD) by using M05-2X/6-311++G^** level of theory. The rotational barrier was considered about the spindle ring from 0° to 180° by 10° intervals. Energies, aromaticity and quadrupole moment values are dependent on the rotation of spindle ring of S-MERD and were plotted as functions of rotation of spindle ring. Rotational barrier of energies, aromaticity and quadrupole moment for all substituents produces a cos²θ function. The nucleus-independent chemical shifts (NICS) of spindle ring increase as the spindle ring gradually rotates out of planarity and reach the highest NICS in the perpendicular conformation. For all substituents, the values of quadrupole moment of spindle ring decrease from 0° to 90° and then increase from 90° to 180°.     

From hypervalent xenon difluoride and aryliodine(III) difluorides to onium salts: Scope and limitation of acidic fluoroorganic reagents in the synthesis of fluoroorgano xenon(II) and iodine(III) onium salts

Fluorinated organodifluoroboranes R_fBF₂ are in general suitable reagents to transform XeF₂ and RIF₂ into the corresponding onium tetrafluoroborate salts [R_fXe][BF₄] and [R(R_f)I][BF₄], respectively. (4-C₅F₄N)BF₂ and trans-CF₃CFCFBF₂ which represent boranes of high acidity form no Xe-C onium salts in reactions with XeF₂ but give the desired iodonium salts with RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄). The reaction of (4-C₅F₄N)BF₂ with XeF₂ ends with a XeF₂-borane adduct. C₆F₅Xe(4-C₅F₄N), the first Xe-(4-C₅F₄N) compound, was obtained when C₆F₅XeF was reacted with Cd(4-C₅F₄N)₂. We describe the synthesis of (4-C₅F₄N)IF₂ and reactions of (4-C₅F₄N)IF₂ and C₆F₅IF₂ with (4-C₅F₄N)BF₂. Analogous to [(4-C₅F₄N)₂I][BF₄] and [C₆F₅(4-C₅F₄N)I][BF₄] aryl(perfluoroalkenyl)iodonium salts [R(R′)I][BF₄] were obtained from RIF₂ (R = C₆F₅, o-, m-, p-C₆FH₄) and R′BF₂ (R′ = trans-CF₃CFCF, CF₂CF). The gas phase fluoride affinities pF⁻ of selected fluoroorganodifluoroboranes R_fBF₂ and their hydrocarbon analogs are calculated (B3LYP/6-31+G^*) and discussed with respect to their potential to introduce R_f-groups into hypervalent EF₂ bonds. Four aspects which influence the transformation of hypervalent EF₂ bonds (E = Xe, R′I) under the action of Lewis acidic reagents RAF_n−1 (A = B, P; n = 3, 5) into the corresponding [RE][AF_n+1] salts are presented and the important role of the acidity is emphasized. Fluoride affinities may help to plan the introduction of organo groups into EF₂ moieties and to expand the types of acidic reagents. Thus C₆H₅PF₄ with a pF⁻ value comparable to that of R_fBF₂ compounds is able to introduce the C₆H₅ group into RIF₂ (R = C₆F₅, p-C₆FH₄).     

Effect of annealing on structural, optical and electrical properties of nanostructured Ge thin films

Ge thin films with a thickness of about 110 nm have been deposited by electron beam evaporation of 99.999% pure Ge powder and annealed in air at 100-500 °C for 2 h. Their optical, electrical and structural properties were studied as a function of annealing temperature. The films are amorphous below an annealing temperature of 400 °C as confirmed by XRD, FESEM and AFM. The films annealed at 400 and 450 °C exhibit X-ray diffraction pattern of Ge with cubic-F structure. The Raman spectrum of the as-deposited film exhibits peak at 298 cm⁻¹, which is left-shifted as compared to that for bulk Ge (i.e. 302 cm⁻¹), indicating nanostructure and quantum confinement in the as-deposited film. The Raman peak shifts further towards lower wavenumbers with annealing temperature. Optical band gap energy of amorphous Ge films changes from 1.1 eV with a substantial increase to ∼1.35 eV on crystallization at 400 and 450 °C and with an abrupt rise to 4.14 eV due to oxidation. The oxidation of Ge has been confirmed by FTIR analysis. The quantum confinement effects cause tailoring of optical band gap energy of Ge thin films making them better absorber of photons for their applications in photo-detectors and solar cells. XRD, FESEM and AFM suggest that the deposited Ge films are composed of nanoparticles in the range of 8-20 nm. The initial surface RMS roughness measured with AFM is 9.56 nm which rises to 12.25 nm with the increase of annealing temperature in the amorphous phase, but reduces to 6.57 nm due to orderedness of the atoms at the surface when crystallization takes place. Electrical resistivity measured as a function of annealing temperature is found to reduce from 460 to 240 Ω-cm in the amorphous phase but drops suddenly to 250 Ω-cm with crystallization at 450 °C. The film shows a steep rise in resistivity to about 22.7 KΩ-cm at 500 °C due to oxidation. RMS roughness and resistivity show almost opposite trends with annealing in the amorphous phase.     

Hydrodynamic Characteristics and Adsorption Particularity of Nanobiological Feedstock Along the Bed Height in a Novel Chromatography Column

Expanded bed adsorption (EBA) is a practical method for the separation of nanoparticulates. In order to analysis the local hydrodynamic and adsorption behavior of nanoparticle (NP)-based biological feedstock, a modified Nano Biotechnology Group EBA column with a 26-mm inner diameter was used to withdraw liquid from different axial positions of the column. Fabricated egg albumin (EA) NPs with an average size of 70 nm were employed as a model system and viral size/charge mimic to assess the relationship between hydrodynamic and adsorption performance of NPs at the different column regions. The effects of influential factors, including flow velocity and initial concentration of NPs, on NP hydrodynamic behavior and adsorption kinetics along the bed height were investigated. NP hydrodynamic studies confirmed that non-uniform behavior dominated the system and a decreasing trend of liquid mixing/dispersion with increase of bed height was observed in this column. The results demonstrated an increase in the mixing/dispersion at certain bed heights with the increase in both the velocity and feed initial concentration. Breakthrough curves were measured at various column points to determine the adsorption performance [dynamic binding capacity (DBC) and yield] in different bed positions/zones. Yield and DBC of NPs were improved along the bed height, whereas liquid velocity had the opposite effect. Increasing the initial concentration of NPs enhanced only the DBC. Separation of EA NPs under optimal conditions was 87 %, which is an excellent result for a one-pass frontal chromatography method.

     

One-pot access to indolo[2,3-b]quinolines by electrophile-triggered cross-amination/Friedel-Crafts alkylation of indoles with 1-(2-tosylaminophenyl)ketones

Activation of C2 and C3 of indoles by molecular iodine (I(2)) and base followed by in situ reaction with 1-(2-tosylaminophenyl)ketones or 2-tosylaminobenzaldehyde can afford highly substituted indolo(2,3-b)quinolines in moderate to excellent yields (up to 99%). The reaction provides a metal-free selective difunctionalization of indoles. The synthetic potential of the protocol has been illustrated by the synthesis of neocryptolepine and its 11-methyl analogue.     

Optical solitons and complexitons of the Schrödinger–Hirota equation

The Schrödinger–Hirota equation governs the propagation of optical solitons in a dispersive optical fiber. In this paper, this equation will be solved by the ansatz method for bright and dark 1-soliton solution. The power law nonlinearity will be assumed. By using the tanh method, some additional solutions will be derived. Finally, the numerical simulations will be given.     

Synthesis,Characterization, In Vitro Anticancer Potentiality,and Antimicrobial Activities of Novel Peptide–Glycyrrhetinic-Acid-Based Derivatives

Glycyrrhetinic acid (GA) is one of many interesting pentacyclic triterpenoids showing significant anticancer activity by triggering apoptosis in tumor cell lines. This study deals with the design and synthesis of new glycyrrhetinic acid (GA)–amino acid peptides and peptide ester derivatives. The structures of the new derivatives were established through various spectral and microanalytical data. The novel compounds were screened for their in vitro cytotoxic activity. The evaluation results showed that the new peptides produced promising cytotoxic activity against the human breast MCF-7 cancer cell line while comparing to doxorubicin. On the other hand, only compounds 3, 5, and 7 produced potent activity against human colon HCT-116 cancer cell line. The human liver cancer (HepG-2) cell line represented a higher sensitivity to peptide 7 (IC₅₀; 3.30 μg/mL), while it appeared insensitive to the rest of the tested peptides. Furthermore, compounds 1, 3, and 5 exhibited a promising safety profile against human normal skin fibroblasts cell line BJ-1. In order to investigate the mode of action, compound 5 was selected as a representative example to study its in vitro effect against the apoptotic parameters and Bax/BCL-2/p53/caspase-7/caspase-3/tubulin, and DNA fragmentation to investigate beta (TUBb). Additionally, all the new analogues were subjected to antimicrobial assay against a panel of Gram-positive and Gram-negative bacteria and the yeast candida Albicans. All the tested GA analogues 1–8 exhibited more antibacterial effect against Micrococcus Luteus than gentamicin, but they exhibited moderate antimicrobial activity against the tested bacterial and yeast strains. Molecular docking studies were also simulated for compound 5 to give better rationalization and put insight to the features of its structure.     

Supercontinuum generation at 1.55μm using highly nonlinear photonic crystal fiber for telecommunication and medical applications

In this paper, we present a theoretical calculation of a highly nonlinear germanium (Ge) doped photonic crystal fiber with all-normal group velocity dispersion to design a supercontinuum (SC) light source at 1.55 μm. By doping 3% higher refractive index Ge inside the host silica, the nonlinear coefficient is increased to a value as large as 60.5 W^?1 km^?1 at 1.55 μm. A 10 dB bandwidth of a 120 nm SC spectrum for a 2.5 ps input optical pulse and a 10 dB bandwidth of a 190 nm SC spectrum for a 1.0 ps input optical pulse have been found using the same fiber length of 200m and input optical power of 18 W. The coherent lengths of the generated SC light sources are found to be 8.8 μm for a 2.5 ps input optical pulse and 5.6 μm for a 1.0 ps input optical pulse. Therefore, the highest longitudinal resolution at 1.55 μm is found to be about 4.0 μm for biological tissues.     

Holography based super resolution

This paper describes the simulation of a simple technique of superresolution based on holographic imaging in spectral domain. The input beam assembly containing 25 optical fibers with different orientations and positions is placed to illuminate the object in the 4f optical system. The position and orientation of each fiber is calculated with respect to the central fiber in the array. The positions and orientations of the fibers are related to the shift of object spectrum at aperture plane. During the imaging process each fiber is operated once in the whole procedure to illuminate the input object transparency which gives shift to the object spectrum in the spectral domain. This shift of the spectrum is equal to the integral multiple of the pass band aperture width. During the operation of single fiber (ON-state) all other fibers are in OFF-state at that time. The hologram recorded by each fiber at the CCD plane is stored in computer memory. At the end of illumination process total 25 holograms are recorded by the whole fiber array and by applying some post processing and specific algorithm single super resolved image is obtained. The superresolved image is five times better than the band-limited image. The work is demonstrated using computer simulation only.