A novel approach for deducing the mass composition of cosmic rays from lateral densities of EAS particles

A Monte Carlo (MC) simulation study of cosmic ray (CR) extensive air showers (EAS) has been carried out in the energy regime of the KASCADE experiment. From the characteristics of lateral distributions of electrons and muons of simulated EAS, some important EAS observables are extracted by a novel approach, and their CR mass-sensitivity is demonstrated. The study takes into account the issue of the experimental lateral density profiles of EAS electrons and muons after introducing the notion of the local age and segmented slope parameters, aimed to extract information on CR mass composition from observed data. The estimated lateral shower age and slope from the analysis of the KASCADE data (KCDC) agrees with the idea of a gradual change of CR mass composition from light to heavy around the knee.Comment: 8 pages, 10 figures, Accepted in a Journa

Chemistry of enediynyl azides: activation through a novel pathway

The spontaneous activation of a nonaromatic enediynyl azide under ambient conditions has been demonstrated. The aromatic enediyne followed the expected cycloaddition with the alkene in the neighbouring arm to form a stable bridged bicyclic enediyne

Synthesis of highly strained enediynes and dienediynes

Enediynes continue to fascinate scientists working in various domains because of their structural complexity and fascinating biological mode of action. They represent a masterpiece of nature's ingenuity. Besides the warhead which is the enediyne moiety, these molecules are equipped with a locking device, a delivery system and a chemical trigger for activation. Upon triggering, the molecules become active and undergo a thermal rearrangement that was disclosed in the early 70 by Masamune and Bergman and commonly known as Bergman cyclization. The reaction is believed to precede through a diradical benzenoid species (a p-benzyne). This review describes the various strategies employed for the synthesis of highly strained enediynes and dienediynes, both naturally occurring and the designed ones

Variability in foliar essential oils among different morphotypes of Lantana species complexes, and its taxonomic and ecological significance

The genus Lantana has many species complexes, and L. camara is one of the aggressive alien weedy species complexes; species delimitation in these complexes is a nightmare for taxonomists. We examined the diversity in the chemical composition of foliar essential oils among morphotypes of Lantana species complexes inhabiting the same ecological gradient, and its taxonomic and ecological significance. The yields of essential oils varied from 0.1 to 0.79% in foliar hydrodistillates of eleven morphotypes, and a total of 39 chemical constituents were detected by GC/MS. The quantitative and qualitative variability in the composition of essential oils among morphotypes was very high, and hence they represent chemotypes. The diversity observed in the composition of essential oils appears to be of genetic origin and thus of taxonomic value. The formation of distinct clusters and sub-clusters at high distance cluster combine values also substantiates that the patterns of distribution of chemical constituents among morphotypes can be used in delimiting species and infraspecific taxa within the species complexes. The presence of β-caryophyllene and other such compounds, which are known to prevent herbivory, in morphotypes of Lantana species complexes suggest that these compounds may provide selective advantage to Lantana over native species in the invasion of new and disturbed habitats