Spectroscopic studies and crystal structure of (E)-N′-(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide

The structure of compound has also been examined cyrstallographically. It crystallizes in the monoclinic space group P2₁/c with a = 7.673(1), b = 16.251(2), c = 10.874(1) Å, β = 110.42(1)°, V = 1270.7(3) ų, D _x = 1.418 g cm^?3, R ₁ = 0.0349 and wR ₂ = 0.0935 [I > 2σ(I)], respectively. The title compound has been synthesized from the reaction of isonicotinohydrazide with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by using elemental analysis, MS, IR, ¹H NMR, ¹³C NMR and UV-Visible spectroscopic techniques.     

Vibrational spectroscopic studies and ab initio calculations of 5-methyl-2-(p-fluorophenyl)benzoxazole

FT-Raman and FT-IR spectra of 5-methyl-2-(p-fluorophenyl)benzoxazole were recorded and analysed. The vibrational frequencies of the compound have been computed using the Hartree-Fock/6-31G* basis and compared with the experimental values.     

Compressive Elastic Moduli of Poly(N‐Isopropylacrylamide) Hydrogels Crosslinked with Poly(Dimethyl Siloxane)

Hydrophobically modified and thermally reversible neutral and ionic copolymer hydrogels were prepared from N‐isopropylacrylamide (NIPAAm), vinyl terminated poly (dimethylsiloxane) (VTPDMS) and itaconic acid (IA) by free radical solution polymerization, and their properties such as swelling ratio and compression modulus were studied at the 25°C. The incorporation of VTPDMS as a hydrophobic macrocrosslinker into the structures of neutral NIPAAm hydrogels increased their mechanical strength around 10 times than those of the ones crosslinked with conventional tetra functional monomer, i.e., N,N′‐methylene bisacrylamide (BIS). Compression modulus decreased with an increase in IA content for ionic samples and increased with increasing molecular weight and content of VTPDMS for neutral samples. It was assumed that in the first case, electrostatic repulsive forces resulting from the ionized carboxyl groups of IA were responsible for decreasing mechanical strength, while in the second case, hydrophobic interactions between dimethylsiloxane units of VTPDMS chains enhanced the compression moduli. According to the results presented in this work, it can be said that the right balance of hydrophobic and hydrophilic constituents and adjustment of the number of ionized groups, as well as crosslinking degree, change the structure and physical properties of NIPPAAm hydrogels.     

Direct acoustic profiling of DNA hybridisation using HSV type 1 viral sequences

We describe the detection of specific, conserved DNA sequences of herpes simplex virus (HSV) type 1 by means of a novel, high sensitivity acoustic biosensor. Repeated assays on planar and polymeric carboxylic acid- and biotin-presenting surface chemistries enabled statistical comparison of assay specificity and sensitivity and evaluation of assay Z-factor scores. Using a three minute hybridisation with NeutrAvidin capture for signal enhancement, it was possible to detect HSV viral nucleic acids at 5.2 x 10(-11) M concentration.     

QSAR of genotoxic active benzazoles

Previously synthesized 2,5-disubstituted benzoxazole and benzimidazole derivatives, were tested for their genotoxic activity in the Bacillus subtilis rec- assay. The results revealed that 5-methyl-2-(p-aminobenzyl)benzoxazole exhibited the highest genotoxic response, which was comparable to 4-nitroquinoline 1-oxide (4-NQO), the reference agent of classical positive mutagen. Among the other tested compounds, four showed a genotoxic activity. A QSAR study revealed that structural parameters IY(C(2)H(4)) and IY(CH(2)O), indicating the bridge elements between the phenyl moiety and the fused ring system at position 2 and the quantum chemical parameter (DeltaE ), showing the difference between HOMO and LUMO energies, were found significant for enhancing the genotoxic activity in these compounds. In addition, the substituent effects on positions R and R(1) were found important for the activity as well as holding a substituent possessing a maximum length with a minimum width property on position R(1) like alkyl groups. On the other hand, substituting position R with an electron donating group instead of electron withdrawing group increased the genotoxic activity.     

The effect of normal electric field on the evolution of immiscible Rayleigh-Taylor instability

Manipulation of the Rayleigh-Taylor instability using an external electric field has been the subject of many studies. However, most of these studies are focused on early stages of the evolution. In this work, the long-term evolution of the instability is investigated, focusing on the forces acting on the interface between the two fluids. To this end, numerical simulations are carried out at various electric permittivity and conductivity ratios as well as electric field intensities using Smoothed Particle Hydrodynamics method. The electric field is applied in parallel to gravity to maintain unstable evolution. The results show that increasing top-to-bottom permittivity ratio increases the rising velocity of the bubble while hindering the spike descent. The opposite trend is observed for increasing top-to-bottom conductivity ratio. These effects are amplified at larger electric field intensities, resulting in narrower structures as the response to the excitation is non-uniform along the interface.