Transfer-printing of highly aligned DNA nanowires

We developed a simple method of reproducibly creating highly aligned DNA nanowires without any surface modifications or special equipment. Stretched DNA molecules initially present on the PDMS sheet were transferred onto another surface using transfer-printing (TP). Fluorescent microscopic and atomic force microscopic images revealed that many DNA molecules were highly aligned on surfaces after TP. Furthermore, it was also possible to realize the two-dimensional assembly of DNA nanowires by repeating TP.     

Well-Orientation Strategy Biosynthesis of Cefuroxime-Silver Nanoantibiotic for Reinforced Biodentine™ and Its Dental Application against Streptococcus mutans

Dental caries results from the bacterial pathogen Streptococcus mutans (S. mutans) and is the maximum critical reason for caries formation. Consequently, the present study aims to evaluate the antibacterial activity of a newly synthesized nanoantibiotic–Biodentine formulation. The silver nanoparticles (ROE-AgNPs) were biosynthesized from the usage of Rosmarinus officinalis L. extract (ROE) and conjugated with cefuroxime to form Cefuroxime-ROE-AgNPs. Using Biodentine™ (BIOD), five groups of dental materials were prepared, in which Group A included conventional BIOD, Group B included BIOD with ROE-AgNPs, Groups C and D included BIOD with Cefuroxime-ROE-AgNPs at concentrations of 0.5% and 1.5% cefuroxime, respectively, and Group E included BIOD with 1.5% cefuroxime. The synthesized ROE-AgNPs or Cefuroxime-ROE-AgNPs were characterized for conjugating efficiency, morphology, particle size, and in vitro release. Minimum inhibitory concentration (MIC) of the cefuroxime, ROE-AgNPs, and Cefuroxime-ROE-AgNPs were additionally evaluated against cefuroxime resistant S. mutans, which furthered antibacterial efficacy of the five groups of dental materials. The UV-Visible spectrum showed the ROE-AgNPs or Cefuroxime-ROE-AgNPs peaks and their formation displayed through transmission electron microscopy (TEM), X-ray diffraction (XRD) pattern, and Fourier transforms infrared (FTIR) analysis. The end result of Cefuroxime-ROE-AgNPs showed conjugating efficiency up to 79%. Cefuroxime-ROE-AgNPs displayed the highest antibacterial efficacy against S. mutans as compared to cefuroxime or ROE-AgNPs alone. Moreover, the MIC of ROE-AgNPs and Cefuroxime-ROE-AgNPs was detected against S. mutans to be 25 and 8.5 μg/mL, respectively. Consequently, Cefuroxime-ROE-AgNPs displayed that a decrease in the MIC reached to more than three-fold less than MIC of ROE-AgNPs on the tested strain. Moreover, Cefuroxime-ROE-AgNPs/BIOD was employed as a novel dental material that showed maximum antimicrobial activity. Groups C and D of novel materials showed inhibitory zones of 19 and 26 mm, respectively, against S. mutans and showed high antimicrobial rates of 85.78% and 91.17%, respectively. These data reinforce the utility of conjugating cefuroxime with ROE-AgNPs to retrieve its efficiency against resistant S. mutant. Moreover, the nanoantibiotic delivered an advantageous antibacterial effect to BIOD, and this may open the door for future conjugation therapy of dental materials against bacteria that cause dental caries.     

Reactions with 3,6‐diaminothieno[2,3‐b]‐pyridines: Synthesis and characterization of several new fused pyridine heterocycles

6‐Aminopyridine‐2(1H)thiones 1 reacting with α‐halo‐compounds 2a–c afforded the alkylthiopyridine derivatives 3a–c which in turn cyclized to the corresponding thieno[2,3‐b]pyridine derivatives 4a–c . Several thieno[2,3‐b]pyridine derivatives 7, 16, 19 , pyrido[3′,2′:4,5]thieno[3,2‐d]pyrimidine derivatives 6a,b, 11a–c, 21 and pyrido[3′,2′:4,5]thieno[3,2‐c]pyridazine derivatives 13, 17 were prepared starting from compounds 4a–c . © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:405–413, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20313     

Reactions with dimethylformamide‐dimethylacetal: Synthesis and reactions of several new pyridine and pyrazolo[3,4‐b]pyridine derivatives

6‐Aminopyridine‐2(1H)‐thiones 1a,b reacted with dimethylformamide‐dimethylacetal (DMF‐DMA) to give the corresponding 6‐{[(N,N‐dimethylamino)methylene]amino}pyridine derivatives 2a,b . The latter compounds reacted with hydrazine hydrate to afford the 3,6‐diamino‐1H‐pyrazolo[3,4‐b]pyridine derivative 4 and 3‐amino‐5‐hydrazino‐1H‐pyrazolo[4′,3′:5,6]pyrido[2,3‐d]pyrimidine derivative 7 , respectively. Compound 4 condensed with DMF‐DMA to yield the 3,6‐bis{[(N,N‐dimethylamino)methylene]amino}‐1H‐pyrazolo[3,4‐b]pyridine derivative 10 , which reacted with malononitrile to give the corresponding pyridopyrazolopyrimidine derivative 15 . © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:399–404, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20312     

Harmonic and Wave Maps Coupled with Einstein’s Gravitation

In this paper we discuss the coupled dynamics, following from a suitable Lagrangian, of a harmonic or wave map ? and Einstein’s gravitation described by a metric g. The main results concern energy conditions for wave maps, harmonic maps from warped product manifolds, and wave maps from wave-like Lorentzian manifolds.     

Theoretical study of the electronic structure of LiX and NaX (X = Rb,Cs) molecules

Adiabatic potential energy, spectroscopic constants, dipole moments, and vibrational levels have been computed for the lowest electronic states of alkali dimers LiX and NaX (X = Rb, Cs). Calculations have been carried with the use of an ab initio approach with core‐potential potentials and full‐valence configuration. Thus, these systems are treated as two‐electron systems. A good agreement is obtained for some lowest states of the molecules studied with available theoretical works. The existence of numerous avoided crossings between electronic states for ¹Σ symmetries is related to the charge‐transfer process in each molecule between its two ionic systems (Li⁺X^?, Li^?X⁺) and (Na⁺X^?, Na^?X⁺). © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Hierarchical supramolecular structuring and dynamical properties of water soluble polyethylene glycol-perylene self-assemblies

The structural and dynamical properties of dilute aqueous solutions of poly(ethylene glycol)-perylene diimides (PEG(n)-PDI) have been investigated by means of static and dynamic light scattering, TEM microscopy, and small-angle X-ray scattering experiments. The amphiphilic PEG(n)-PDI molecules first self-assemble into stable and compact primary stacks of a few units of planar PDI through hydrophobic and π-π interactions. These primary stacks subsequently arrange in large and globular aggregates of typically 100-250 nm via weak PEG chain interpenetration. Surprisingly, the scattered electric field autocorrelation function g((1))(q,t) measured by dynamic light scattering evolves over very long periods of times (several months) and up to a bimodal distribution. The fast relaxation mechanism is associated to the diffusion of free primary stacks, whereas the slower relaxation still indicates the presence of large self-assemblies. Kinetic experiments show that the large supramolecular aggregates slowly release the free primary stacks whose proportion increases with time. This dissociation depends on several parameters such as PEG side chain length, total concentration, and shaking.     

Ab initio adiabatic and diabatic energies and dipole moments of the CaH+ molecular ion

The diabatic and adiabatic potential-energy curves and permanent and transition dipole moments of the highly excited states of the CaH(+) molecular ion have been computed as a function of the internuclear distance R for a large and dense grid varying from 2.5 to 240 au. The adiabatic results are determined by an ab initio approach involving a nonempirical pseudopotential for the Ca core, operatorial core-valence correlation, and full valence configuration interaction. The molecule is thus treated as a two-electron system. The diabatic potential energy curves have been calculated using an effective metric combined to the effective Hamiltonian theory. The diabatic potential-energy curves and their permanent dipole moments for the (1)∑(+) symmetry are examined and corroborate the high imprint of the ionic state in the adiabatic representation. Taking the benefit of the diabatization approach, correction of hydrogen electron affinity was taken into account leading to improved results for the adiabatic potentials but also the permanent and transition electric dipole moments.     

Effect of Hall currents on interaction of pulsatile and peristaltic transport induced flows of a particle-fluid suspension

The interaction of purely periodic mean flow with a peristaltic induced flow is investigated within the framework of a two-dimensional analogue. The mathematical model considers a viscous incompressible fluid under the effect of transverse magnetic field, taking into account the effect of Hall currents for a magneto-fluid with suspended particles between infinite parallel walls on which a sinusoidal traveling wave is imposed. A perturbation solution to the complete set of Navier-Stokes equations is found for the case in which the frequency of the traveling wave and that of the imposed pressure gradient are equal. The ratio of the traveling wave amplitude to channel width is assumed to be small. For this case a first order steady flow is found to exist, as contrasted to a second order effect in the absence of the imposed periodic pressure gradient. The effect of Hall parameter, Hartmann number and the various parameters included in the problem are discussed numerically.