A rapid and convergent synthesis of the integrastatin core

The tetracyclic core of the integrastatin natural products has been prepared in a convergent and rapid manner. Our strategy relies upon a palladium(II)-catalyzed oxidative cyclization to form the central [3.3.1]-dioxabicycle of the natural product core. Overall, the core has been completed in only 4 linear steps from known compounds.     

A rapid and simple route for the synthesis of lead and palladium nanoparticles in tetrazolium based ionic liquid

In the present work, we report a novel method for the synthesis of palladium and lead nanoparticles by the reduction method in tetrazolium ring based ionic liquid. Palladium and lead nanoparticles so-prepared were well characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed all relevant Bragg's reflection for crystal structure of palladium and lead. Powder X-ray diffraction plots also revealed no oxidized material of palladium and lead nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of palladium nanoparticles include in vitro use and sensor design applications. Palladium nanoparticles is also ideal for spin coating, self-assembly and monolayer formation. Palladium nanoparticles can also be considered as potential new catalysts.     

On p-class groups of relative cyclic p-extensions

Archiv der Mathematik - We prove a general stability theorem for p-class groups of number fields along relative cyclic extensions of degree $$p^2$$ , which is a generalization of a finite-extension...     

Single‐Cell Investigations of Silver Nanoparticle–Bacteria Interactions

Interaction of bacteria with citrate‐reduced silver nanoparticles (AgNPs) of size 25 nm ± 8.5 nm is studied using Raman spectroscopy in conjunction with plasmon resonance imaging of single bacterial cells. Distribution of isolated nanoparticles (NPs) inside Escherichia coli (ATCC 25922; E. coli) is observed by hyperspectral imaging (HSI) as a function of incubation time. Time‐dependent degradation of bacterial DNA upon incubation of AgNPs with E. coli is proven by Raman spectroscopic studies. While attachment of NPs is evident in HSI, molecular changes are evident from the surface‐enhanced Raman spectra of adsorbed DNA and its fragments. Distinct enhancement of DNA features is observed upon interaction of AgNPs and the number of such distinct features increases with incubation time, reaches a maximum, and decreases afterwards. This systematic interaction of DNA with the NPs system and its gradual chemical evolution is proven by investigating isolated plasmid DNA. A comparative Raman study with silver ions has shown that DNA features are observable only when bacteria are incubated with AgNPs. Energetics of interaction examined with microcalorimetry suggests the exothermicity of ?1.547 × 10¹⁰ cal mol^?1 for the NP–bacteria system. Specific interaction of AgNPs with exocyclic nitrogen present in the bases, adenine, guanine, and cytosine, leads to the changes in DNA.     

Centrifugal distortion analysis of the millimeter-wave spectrum of 2-fluorobenzonitrile and ab initio DFT calculations

The ground state (ν = 0) rotational spectrum of 2-fluorobenzonitrile has been reinvestigated in the frequency range 40.0-99.0 GHz. The millimeter-wave spectrometer used is a source-modulated system combined with a free space glass cell. Millimeter-wave radiation has been produced using a Gunn diode and frequency doubler combination. High J and K₋₁ (J ? 49 and K₋₁ ? 18) transitions have been measured and accurate rotational and centrifugal distortion constants have been determined. Finally, the experimental values were compared with the corresponding values calculated at the HF/DFT-B3PW91/6-31g(d,p) level of theory. A very good agreement has been found.     

A micro-convection model for thermal conductivity of nanofluids

Increase in the specific surface area as well as Brownian motion are supposed to be the most significant reasons for the anomalous enhancement in thermal conductivity of nanofluids. This work presents a semi-empirical approach for the same by emphasizing the above two effects through micro-convection. A new way of modeling thermal conductivity of nanofluids has been explored which is found to agree excellently with a wide range of experimental data obtained by the present authors as well as the data published in literature     

Information patterns and Nash equilibria in extensive games — II

In Part I of this paper we introduced extensive games with a non-atomic continuum of players. It was shown that the Nash plays (outcomes) are invariant of the information patterns on the game, provided that no player's unilateral change in moves can be observed by others. This led to an enormous reduction in the Nash plays of the these games, as exemplified in the anti-folk theorem. Our concern in this sequel is to develop a finite version of these results.     

Differential cross sections for the charge exchange process π+p → π0 (π+p) at 8, 16 and 23 GeV/c

The differential cross section $\text{d}\text{σ}\text{d}\text{t′}$ for the charge-exchange process π⁺p → π⁰ (π⁺p) at 8, 16 and 23 GeV/c is presented for several regions of the π⁺p effective mass. It is found that the dip at t′ ≈ 0.6 (GeV/c)² which is observed in the Δ(1236) mass band becomes a less pronounced structure in the higher mass regions. However, while the slope of the $\text{d}\text{σ}\text{d}\text{t′}$ distributions in the near-forward direction decreases strongly with increasing π⁺p mass, there is no evidence that the observed structure moves to higher values of t′ as the π⁺p mass increases. These results are consistent with a Regge-exchange picture where the position of the dip is determined by the exchanged trajectory, but are inconsistent with a simple geometrical picture.     

Oxide films of copper prepared by the oxidation of copper sulphide films

Copper sulphide films prepared by reactive evaporation, when heated in air at 500 K, oxidized to Cu₂O after a series of intermediate chemical transitions. Golden yellow coloured Cu₂O films showed a large absorption before the fundamental absorption edge. The optical band gap was found to be (2.29±0.02)eV. When these Cu₂O films were further heated they got converted to CuO and the optical band gap was found to be (2.17±0.02)eV.