A simple microscopic model for the dynamics of adhesive failure

We consider a microscopic model for the failure of soft adhesives in tension based on ideas of bond rupture under dynamic loading. By focusing on adhesive failure under loading at constant velocity, we demonstrate that bimodal curves of stress against strain may occur due to effects of finite polymer chain or bond length and characterize the loading conditions under which such bimodal behavior is observed. The results of this analysis are in qualitative agreement with experiments performed on unconfined adhesives in which failure does not occur by cavitation.     

An efficient synthesis of pharmacologically active derivatives of 1,3,4‐oxadiazoles

A simple and environmental friendly microwave irradiation method is devised for the synthesis of derivatives of 1,3,4‐oxadiazoles viz., 6a‐e and 7h‐q in 75–90% yield. Structures of the newly synthesised compounds were confirmed by physical, analytical and spectral (ir, ¹H and ¹³C nmr and ms) data and screened for antiinflammatory, anticonvulsant, antidiuretic and antihaemostatic activities. Some of the compounds have shown potent activities.     

Enhancement of stability of growth,structural and NLO properties of KDP crystals due to additive along with seed rotation

Potassium Acetate (CH₃COOK) and Potassium Citrate (K₃C₆H₅O₇) as new additives were added into the potassium dihydrogen phosphate (KDP) solutions in different molar ratios. The metastable zone width and induction period with and without these additives were determined and compared. Dielectric measurements on pure and doped KDP crystals at various temperatures ranging from 313 to 423 K were carried out by the conventional parallel plate capacitor method which results low dielectric constant value dielectrics in doped crystals. The high resolution XRD studies show that CH₃COOK doped KDP crystal and K₃C₆H₅O₇ doped KDP crystal do not contain any internal structural grain boundaries and indicates that the crystalline perfection is very good. Moreover, the addition of these potassium additives improves the quality of the crystal and yields highly transparent crystals with well defined features. The effect of additives on the growth, nucleation kinetics, structural, NLO and optical properties has been investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,Spectral, Solvent Dependent Linear and Nonlinear Optical Characteristics of (E)-N-(3-(3-(4(dimethylamino)phenyl)acryloyl) phenyl)quinolone-2-carboxamide

This paper presents the synthesis of novel organic compound (E)-N-(3-(3-(4(dimethylamino)phenyl)acryloyl)phenyl)quinolone-2-carboxamide, also known as Quinolinecarboxamide Chalcone (QCC) using aldol condensation and carboxamide formation method. The organic sample QCC was examined by FT-IR, ¹H NMR, ¹³C NMR and mass spectroscopic techniques, respectively. Linear and third-order nonlinear optical (TNLO) properties of QCC dissolved in polar solvents such as DMSO, DMF and Ethanol have also been studied. The order of nonlinear refractive index and nonlinear absorption coefficient of QCC was measured to be 10^?11 m²/W and 10^?5 m/W. The nonlinear refractive index (n₂) of QCC was attributed to negative nonlinearity due to self-defocusing effect, and nonlinear absorption coefficient (β) indicates the behaviors of saturable absorption (SA) and reverse saturable absorption (RSA). The real and imaginary features of the TNLO susceptibility (χ⁽³⁾) of QCC in polar solvents were calculated to be the order of 10^─7 esu. The spectral characteristics of solvent on TNLO susceptibility of QCC were discussed. The results divulged that the synthesized organic compound is a novel nonlinear optical (NLO) material for applications in photonics and optoelectronics.

     

Defect induced local moment in ZnO as a consequence of Stoner mechanism

We have examined the formation of a local moment by considering various defects in ZnO. The localization of the defect induced state is found to determine the presence/absence of a local moment. A lot of attention on the probable origin of magnetism in wide band gap oxides has focused on cation vacancies. Here we show that oxygen interstitial atoms give rise to a large magnetic moment which results in a spin polarization of both the conduction and valence bands, in addition to spin polarized gap states. A Stoner mechanism is invoked and the relevant Stoner parameters are determined to be 0.7 eV for an oxygen atom in the presence of an oxygen interstitial but reduced to 0.2 eV on oxygen in the presence of a Zn vacancy.     

A potassium–18-crown-6 salt of a cyclic myo-inositol phosphate

The six-membered phosphorinane ring in (1,4,7,10,13,16-hexaoxa­cyclo­octa­decane)­potassium 2-O-benzoyl-1,3,5-O-methyl­idyne-myo-in­osi­tol 4,6-cyclo­phosphate trihydrate, [K(C₁₂H₂₄O₆)](C₁₄H₁₂O₉P)·3H₂O, has a boat rather than a chair conformation. The K⁺ ion is eight-coordinate and is connected to one of the phosphate O atoms, one of the O atoms of the myo-inositol residue and the six O atoms of the crown ether.     

High-throughput screening assay for the quantification of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 in HepG2 cells using RapidFire mass spectrometry

Ceramides are known to be involved in various biological processes with their physiological levels elevated in various disease conditions such as diabetes, Alzheimer's, atherosclerosis. To facilitate the rapid screening of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 inhibition in HepG2 cells, a RapidFire coupled to tandem mass spectrometry (RF–MS/MS) method has been developed. The RF platform provides an automated solid-phase extraction system that gave a throughput of 12.6 s per sample to an MS/MS system using electrospray ionization under the positive ion mode. Chromatographic separation of Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, and d18:1/22:0 was achieved using a ternary gradient on C₈ type E cartridge. The MS/MS ion transitions monitored were 538.2 → 264.2, 650.7 → 264.2, 648.6 → 264.2, 566.4 → 264.2, 510.4 → 264.2, 594.4 → 264.2, 622.5 → 264.2, and 552.3 → 250.2 for Cer d18:1/16:0, d18:1/24:0, d18:1/24:1, d18:1/18:0, d18:1/14:0, d18:1/20:0, d18:1/22:0, and the internal standard (Cer d17:1/18:0), respectively. The RF–MS/MS methodology showed an excellent performance with an average Z′ value of 0.5–0.7. This is the first report of an RF–MS/MS assay for screening of ceramides which is amenable for high-throughput screening.     

Tuning of Bistability,Thermal Stability of the Metastable States,and Application Prospects in the C3-Symmetric Designs of Multiple Azo(hetero)arenes Systems

Light-responsive molecular systems with multiple photoswitches in C₃-symmetric designs have enormous application potential. The design part of such molecular systems is critical due to its influence in several properties associated with the photoswitches. In order to tune, and in the evaluation of the design–property relationship, we synthesized 18 tripodal systems with variations in the core, linkers, connectivity, and azo(hetero)arene photoswitches. Through extensive spectroscopic and computational studies, we envisaged the factors controlling near-quantitative photoisomerization in both the directions (bistability) and the thermal stability of the metastable states. Furthermore, we also evaluated the impact of designs in obtaining reversible photo-responsive sol-gel phase transitions, solvatochromism, photo- and thermochromism.