Effect of photons on the magnon splitting

The self energy of a uniform magnon due to splitting into two magnons of oppositely directed momenta is calculated in the presence of a magnon-photon interaction, and it is found that the magnons and the photons form excitations of mixed character. Thus there is a net correction to the magnon splitting due to an interference.     

Indium triflate promoted one-pot multicomponent synthesis of structurally diverse 3-amino-imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridines

An efficient, mild, and expeditious synthetic protocol has been developed for the synthesis of structurally diverse 3-amino-imidazo[1,2-a]pyridines, involving a three-component, one-pot cyclocondensation reaction of 2-aminobenzothiazole/2-aminoazines, ethyl isocyanoacetate/tert-butyl isocyanides, and pyrazole-3(4)-carbaldehyde/substituted aromatic carbonyl compounds in 45 min. using In(OTf)\(_{3}\) as a catalyst in toluene. Mild reaction conditions, high atom economy, operational simplicity, short reaction time, and structural diversity with high product conversion are among the advantages of the present synthetic protocol.     

Cosmic (Super)String Constraints from 21 cm Radiation

We calculate the contribution of cosmic strings arising from a phase transition in the early Universe, or cosmic superstrings arising from brane inflation, to the cosmic 21 cm power spectrum at redshifts z > or =30. Future experiments can exploit this effect to constrain the cosmic string tension G mu and probe virtually the entire brane inflation model space allowed by current observations. Although current experiments with a collecting area of approximately 1 km2 will not provide any useful constraints, future experiments with a collecting area of 10(4)-10(6) km2 covering the cleanest 10% of the sky can, in principle, constrain cosmic strings with tension G mu > or = 10(-10)-10(-12) (superstring/phase transition mass scale >10(13) GeV).     

Effect of animal drawn puddling implements on hydraulic conductivity of lateritic sandy clay loam soil in West Bengal, India

To determine out the suitable animal drawn puddling implement in terms of reduction in hydraulic conductivity of soils were investigated in this research study. In rice (Oriza sativa L.) cultivation in West Bengal, India, reduction in hydraulic conductivity of soil facilitates better rice growth. To determine, the effect of puddling implements, i.e., an animal drawn rotary puddler (I₁), a 3-tine tiller (I₂) and a local plough (I₃), and number of passes of the implements on hydraulic conductivity of the puddled as well as the non-puddled layer of a lateritic sandy clay loam with respect to relative age (i.e., elapsed time after puddling operation) was studied under controlled soil-bin conditions. It was concluded that the hydraulic conductivity of soil decreases with the number of passes and relative age. A mathematical model was developed for calculating the hydraulic conductivity of puddled soil layer. It was concluded that the hydraulic conductivity obtained with the rotary puddler was 2.27 times less than that with the 3-tine tiller and 3.09 times that with local plough after the fifth pass of puddling operations.     

Sugarcane Bagasse Ash-Based Silica-Supported Boric Acid (SBA-SiO2-H3BO3): A Versatile and Reusable Catalyst for the Synthesis of 1,4Dihydropyrano[2,3c]pyrazole Derivatives

Russian Journal of Organic Chemistry - A simple, green, and efficient protocol has been developed for the synthesis of biologically active 1,4dihydropyrano[2,3c]pyrazole derivatives via one-pot...     

Optical and electrical control of circularly polarised fluorescence in CdSe quantum dots dispersed polymer stabilised cholesteric liquid crystal shutter

In the present communication, we report on the synthesis and electro-optic investigation of photosensitive CdSe quantum dots (QDs) dispersed polymer stabilised liquid crystal (PSCLC) luminescent gel. The assembly of the fluorescence properties of CdSe QDs facilitate the anisotropy of PSCLC gel and hence manipulates the optical and electro-optic switching properties, which was further investigated using polarised fluorescence spectrophotometer. The circularly polarised fluorescence intensity was tuned electrically so as to affect the orientations of liquid crystal in the helix. It was found that the electro-optic switching behaviour of QDs-doped sample predicts the improvement in threshold voltage and hence makes them applicable for the switchable liquid crystal contrivances with low power consumption.     

Density-Functional Theory of Vibrations in Ni<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>V<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> Clusters

We have performed the calculation of the vibrational frequencies, Fermi energy and binding energy for several clusters of Ni and vanadium atoms by using the first principles. The calculations are performed by using the density-functional theory in the local-density approximation with spin polarized orbitals. The calculation of vibrational frequencies shows that some of the clusters have positive vibrational frequencies which describe the oscillations of the stable clusters. The negative vibrational frequencies indicate that these clusters are instable with respect to these vibrations when no energy of this frequency is supplied. We find that for vanadium concentration less than 11.1% the clusters of Ni and V atoms are not stable. Hence ferromagnetism in Ni is predicted below 11.1% vanadium. We find the vibrational frequencies of several clusters for which the vanadium concentration is more than 11.1%. We are able to find a phase transition by use of quantum mechanics alone without the use of classical mechanical variables or thermodynamic variables such as temperature.     

HPLC quantification of the HIV-1 protease inhibitor saquinavir in brain and testis of mice

A rapid, reliable HPLC method with UV detection (240 nm) was developed and validated for quantitation of saquinavir in mice brain and testis. Saquinavir and the internal standard were isolated from homogenized tissue matrices using liquid-liquid extraction procedure and were then analyzed using an isocratic mobile phase by reversed-phase liquid chromatography. The lower limit of quantification was 50 ng/g for both brain and testis. A linear dynamic range of 50-5000 ng/g for both brain and testis was established. This HPLC method was validated with between-batch precision of 0.5-4.4 and 1.5-5.5% for brain and testis, respectively. The between-batch accuracy was 94.7-105.9% and 97.5-105.0% for brain and testis, respectively. The present method was applied for tissue distribution studies of the novel drug delivery systems of saquinavir in mice.     

The vorticity jump across a stationary magnetogasdynamic discontinuity

Résumé La condition du saut de vorticité est obtenue à travers une discontinuité magnéto-dynamique dans un gaz. On montre que la conclusion de Hayes pour la dérivation du saut de vorticité à travers une discontinuité dynamique dans un gaz n'est pas valable à travers une discontinuité magnéto-dynamique dans un gaz. On montre aussi que les résultats obtenus ne sont pas limités aux ondes de choc, mais valent également pour les ondes de la détonation et de la condensation. Les résultats concernant quelques cas particuliers intéressants ont aussi été déduits et discutés.