Toward a practical and waste-free synthesis of thioureas in water

An operationally simple and entirely green protocol for the synthesis of thiourea derivatives by the reaction of carbon disulfide with primary amines in pure water is developed. This reaction is a highly atom-economic process for production of highly pure, hindered thioureas without any catalyst and tedious work-up.     

Statistical isotropy of the cosmic microwave background

The breakdown of statistical homogeneity and isotropy of cosmic perturbations is a generic feature of ultra-large scale structure of the cosmos, in particular, of non-trivial cosmic topology. The statistical isotropy (SI) of the cosmic microwave background temperature fluctuations (CMB anisotropy) is sensitive to this breakdown on the largest scales comparable to, and even beyond the cosmic horizon. We propose a set of measures,K _l (l = 1, 2,3,...) which for non-zero values indicate and quantify statistical isotropy violations in a CMB map. We numerically compute the predictedK _l spectra for CMB anisotropy in flat torus universe models. Characteristic signatures of different models in theK _l spectrum are noted.     

Quantitative optical imaging of the pharmacokinetics of fluorescent-specific antibodies to tumor markers through tissuelike turbid media

Fluorescent optical imaging of tumors deep within tissue depends on specific binding of antibodies to the tumors' surface markers. These fluorescent antibodies propagating in the vicinity of the tumor can be attached to and (or) diffused away from it. We illustrate application of a new tool, based on the random-walk theory in turbid media, for extracting the pharmacokinetics of these fluorescent antibodies by data deconvolution, excluding the effect of upper turbid tissue layers.     

Simple Analytical Model of the Anodic Streamer

In this work, an analytical model is used to study the formation of the anodic streamer in high pressure electrical discharge. This model enabled us to see the space variations of the characteristics of the streamer such as the electric field and the propagation velocity of streamer. The validity of the analytic approach is demonstrated by comparing the model results to the data from the literature. A qualitative concord was found. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Laser based fabrication of chitosan mediated silver nanoparticles

We report fabrication of silver nanoparticles (Ag NPs) by laser ablation technique in different concentrations of aqueous chitosan solution. The ablation process of silver plate was carried out by using a nanosecond Q-switched Nd:YAG pulsed laser and the characterization of Ag NPs was done by Transmission electron microscopy, UV-Vis spectroscopy, and X-ray diffraction. UV-visible plasmon absorption spectra revealed that the formation efficiency as well as the stability of nanoparticles was increased by addition of chitosan. On the other hand, the size decrement of nanoparticles was more remarkable in the higher chitosan concentration.     

Bidirectional Quantum Teleportation of a Class of <Emphasis Type="Italic">n</Emphasis>-Qubit States by Using (2<Emphasis Type="Italic">n</Emphasis> + <Emphasis Type="Bold">2</Emphasis>)-Qubit Entangled States as Quantum Channel

A new protocol of bidirectional quantum teleportation (BQT) is proposed in which the users can transmit a class of n-qubit state to each other simultaneously, by using (2n + 2)-qubit entangled states as quantum channel. The state of the art approaches can only transmit two-qubit states in each round. This scheme is based on control-not operation, single-qubit measurements and appropriate single-qubit unitary operations. It is shown that the protocol is secure in preparation phase.     

Microwave-assisted green synthesis of 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-1-carbothioamides in water

Rapid, efficient, simple and green procedure for the synthesis of 4,5-dihydro-1H-pyrazole-1-carbothioamides via the multicomponent reaction of aryl aldehydes, acetophenones and thiosemicarbazide in water in the presence of tetrabutylammonium hydroxide under microwave irradiation is reported.     

Sulfamic acid catalyzed solvent-free synthesis of 10-aryl-7,7-dimethyl-6,7,8,10-tetrahydro-9H-[1,3]-dioxolo [4,5- <Emphasis Type="Italic">b</Emphasis>]xanthen-9-ones and 12-aryl-9,9-dimethyl-8,9,10,12-tetrahydro-11H-benzo[<Emphasis Type="Italic">a</Emphasis>]xanthen-11-ones

Three-component one-pot synthesis of some novel 10-aryl-7,7-dimethyl-6,7,8,10-tetrahydro-9H-[1,3]-dioxolo[4,5-b]xanthen-9-ones, which have not been published before, and 12-aryl-9,9-dimethyl-8,9,10,12-tetrahydro-11H-benzo[a]xanthen-11-ones from condensation of 3,4-methylenedioxyphenol or β-naphthol, aldehydes and dimedone under solvent-free conditions at 120 °C is reported.     

Enhanced Kerr nonlinearity in a quantized four-level graphene nanostructure

In this paper, a new model is proposed for manipulating the Kerr nonlinearity of right-hand circular probe light in a monolayer of graphene nanostructure. By using the density matrix equations and quantum optical approach, the third-order susceptibility of probe light is explored numerically. It is realized that the enhanced Kerr nonlinearity with zero linear absorption can be provided by selecting the appropriate quantities of controllable parameters, such as Rabi frequency and elliptical parameter of elliptical polarized coupling field. Our results may be useful applications in future all-optical system devices in nanostructures.