A Convenient Synthesis of Cephem-1R-sulfoxides

7-Amidocephalosporins are converted to the 7-diacylaminocephalosporins, which are oxidised exclusively to the 7-diacylamino-1α-sulfoxides. These compounds with benzylamine produce the 7-amidocephem-1α-sulfoxides.     

Disseminating a warning message to evacuate: A simulation study of the behaviour of neighbours

Large-scale evacuations are a recurring theme on news channels, whether in response to major natural or manmade disasters. The role of warning dissemination is a key part in the success of such large-scale evacuations and its inadequacy in certain cases has been a ‘primary contribution to deaths and injuries’ (Hayden et al., 2007). Along with technology-driven ‘official warning channels’ (e.g. sirens, mass media), the role of unofficial channel (e.g. neighbours, personal contacts, volunteer wardens) has proven to be significant in warning the public of the need to evacuate. Although post-evacuation studies identify the behaviours of evacuees as disseminators of the warning message, there has not been a detailed study that quantifies the effects of such behaviour on the warning message dissemination. This paper develops an Agent-Based Simulation (ABS) model of multiple agents (evacuee households) in a hypothetical community to investigate the impact of behaviour as an unofficial channel on the overall warning dissemination. Parameters studied include the percentage of people who warn their neighbours, the efficiency of different official warning channels, and delay time to warn neighbours. Even with a low proportion of people willing to warn their neighbour, the results showed considerable impact on the overall warning dissemination.     

Effect of rotation in magneto-thermoelastic transversely isotropic hollow cylinder with three-phase-lag model

This article deals with the various heat source responses in a transversely isotropic hollow cylinder under the purview of three-phase-lag (TPL) generalized thermoelasticity theory. In presence of magnetic field and due to the rotating behavior of the cylinder, the governing equations are redefined for generalized thermoelasticity with thermal time delay. In order to obtain the stress, displacement and temperature field, the field functions are expressed in terms of modified Bessel functions in Laplace transformed domain. When the outer radius of hollow cylinder tends to infinity, the corresponding results are discussed. Finally an appropriate Laplace transform inversion technique is adopted.     

MCRs reshaped into a switchable microwave-assisted protocol toward 5-aminoimidazoles and dihydrotriazines

A tunable microwave-assisted protocol for the synthesis of two biologically relevant families of heterocycles has been designed. Via a simple switch of reaction conditions, the same starting materials can be engaged in either an improved synthesis of the dihydrotriazine scaffold or a novel, first-in-class MCR to render the challenging 5-aminoimidazole nucleus in a single step. An additional first-in-class MCR is also reported utilizing guanidines to afford 2,5-aminoimidazoles.     

X-RAY CRYSTALLOGRAPHIC AND 35CL N.Q.R. SPECTROSCOPIC STUDIES ON CHLOROCYCLOPHOSPHAZENES

Abstract

X-ray crystallographic structure determinations on a number of chlorocyclophosphazenes are compared with ³⁵Cl N.Q.R. spectroscopic studies of these compounds. Phase changes have been observed.     

THE REACTIONS OF N3P3CL6 AND RELATED COMPOUNDS WITH DIFUNCTIONAL REAGENTS. COMPARISONS AND CONTRASTS

Abstract

The reactions of N₃P₃Cl₆ with a variety of difunctional reagents are discussed. NMR spectroscopic and X-ray crystallographic investigations are presented.     

MASS SPECTROMETRIC STUDIES ON SPIROCYCLIC DERIVATIVES OF CYCLODIPHOSPH(V)AZANES

Abstract

The formation and subsequent fragmentation of spirocyclodiphosph(V)azanes (II-III) has been studied by mass spectrometry using the link-field scan technique and structural inferencies are drawn from these data. ³¹P nmr measurements for compound (III) are also described.     

Dynorphin A 1–17 biotransformation in inflamed tissue, serum and trypsin solution analysed by liquid chromatography–tandem mass spectrometry

Dynorphin A 1–17 (DYN A) is an endogenous neuropeptide that is of interest due to its diverse roles in analgesia, inflammation and addiction. Upon release, DYN A is subject to metabolism by a range of enzymes and its biotransformation is dependent on the site and environment into which it is released. In this study, we investigated the biotransformation of DYN A in rat inflamed tissue at pH?7.4 and 5.5, in rat serum and in trypsin solution. DYN A-porcine was incubated at 37?°C in each matrix over a range of incubation periods. The resultant fragments were separated using a C4 column and detected by mass spectrometry using total ion current mode. Incubation of DYN A in trypsin solution and in rat serum resulted in 6 and 14 fragments, respectively. Incubation in inflamed rat paw tissue occasioned 21 fragments at pH?7.4 and 31 fragments at pH?5.5. Secondary breakdown of some larger primary fragments was also observed in this study.     

FTIR analysis of the hydrolysis rate in the sol–gel formation of gadolinia-doped ceria with acetylacetonate precursors

This study reveals that Fourier transform infrared is an effective analytical tool in probing the extent of hydrolysis of cerium and gadolinium acetylacetonates dissolved in methanol. It is found that these acetylacetonates have relatively fast hydrolysis rates at the early stage of hydrolysis (<6 h). However, their hydrolysis rates become very slow beyond 6-h of hydrolysis and decrease to near zero after 55-h of hydrolysis. As a result, hydrolysis cannot be completed even after 170 h at room temperature. These phenomena suggest that the first and second acetylacetone ligands chelated to Ce³⁺ and Gd³⁺ ions can actually be hydrolyzed with relative ease at room temperature, similar to alkoxide ligands. It is the last acetylacetone ligand that is very difficult to be hydrolyzed.