Chemical composition and evaluation of the antimicrobial activity of the essential oil from leaves of Eugenia platysema

This study describes the qualitative and quantitative chemical composition and evaluates the antibacterial activity of essential oil from Eugenia platysema leaves. Analysis by GC–FID and GC–MS allowed the identification of 22 compounds. Different from the other species of the Eugenia genus, the major compound found in the essential oil was the diterpene phytol (66.05%), being this the first report of the presence of this compound in the essential oils from Eugenia genus. The sesquiterpene elixene was the second most concentrated compound in the studied essential oil (9.16%). The essential oil from E. platysema was tested for its antibacterial activity against cell-walled bacteria and mollicute strains of clinical interest using the microdilution broth assay. The results showed that the essential oil of E. platysema was inactive until 1000 μg mL^?1 against tested bacteria.     

A Non-Standard Analysis of a Cultural Icon: The Case of Paul Halmos

We examine Paul Halmos’ comments on category theory, Dedekind cuts, devil worship, logic, and Robinson’s infinitesimals. Halmos’ scepticism about category theory derives from his philosophical position of naive set-theoretic realism. In the words of an MAA biography, Halmos thought that mathematics is “certainty” and “architecture” yet 20th century logic teaches us is that mathematics is full of uncertainty or more precisely incompleteness. If the term architecture meant to imply that mathematics is one great solid castle, then modern logic tends to teach us the opposite lesson, namely that the castle is floating in midair. Halmos’ realism tends to color his judgment of purely scientific aspects of logic and the way it is practiced and applied. He often expressed distaste for nonstandard models, and made a sustained effort to eliminate first-order logic, the logicians’ concept of interpretation, and the syntactic vs semantic distinction. He felt that these were vague, and sought to replace them all by his polyadic algebra. Halmos claimed that Robinson’s framework is “unnecessary” but Henson and Keisler argue that Robinson’s framework allows one to dig deeper into set-theoretic resources than is common in Archimedean mathematics. This can potentially prove theorems not accessible by standard methods, undermining Halmos’ criticisms.     

Carborane inclusion chemistry for the uncommon calix[7,9]arenes

The inclusion of o-carborane by p-Bu(t)-calix[7,9]arenes has been investigated by solid state and solution studies, with both resulting complexes in the solid state being rich in carborane with the ratio of calixarene to carborane at 1 : 7 and 2 : 7 respectively. The carboranes reside in clefts within the calixarenes which arise from specific local conformations of adjacent phenolic groups, or are included in the extended structure through other interplay of the calixarenes and carboranes in such clefts.     

A version of Fabry's theorem for power series with regularly varying coefficients

For real power series whose non-zero coefficients satisfy , we prove a stronger version of Fabry's theorem relating the frequency of sign changes in the coefficients and analytic continuation of the sum of the power series.

     

Banach Spaces with Property (M) and their Szlenk Indices

We show that a separable Banach space with property (M*) has a Szlenk index equal to ω₀, and a norm with an optimal modulus of asymptotic uniform smoothness. From this we derive a condition on the Szlenk functions of the space and its dual which characterizes embeddability into c ₀ or an ℓ _p -sum of finite dimensional spaces. We also prove that two Lipschitz-isomorphic Orlicz sequence spaces contain the same ℓ _p -spaces.      

Assessable consequences of through-bond donor-acceptor interactions in beta-aminoketones

Reported are the syntheses of ester-functionalized (6-8) and alkyl-substituted (9) 1-aza-adamantanones; the easy handling of the compounds provides an opportunity to comprehensively study the fundamental changes in structure and reactivity that can accompany the donor-acceptor arrangement in rigid beta-aminoketones. X-ray structural analysis of trione 6 and dione 7 reveals bond length and angle variations consistent with through-bond (hyperconjugative) donor-acceptor interactions. Observed is a shortening of the C-N bond, elongation of the central C-C bond (to approximately 1.6 A), and a significant pyramidalization of the carbonyl carbon within the donor-sigma-acceptor pathway. UV/Vis spectra of 6-9 show a new absorption maximum (lambda(max)=260-275 nm in three solvents), the so-called "sigma-coupled transition"; the molar absorptivity scales with the number of carbonyl groups (for trione 6, epsilon approximately 3000, for dione 7, epsilon approximately 2000) and the band reversibly disappears upon addition of acid. IR and (13)C NMR spectroscopic data show trends consistent with through-bond donation to the carbonyl acceptor groups and commensurate weakening of the carbonyl pi bond. High yielding acid-mediated fragmentations are used to illustrate the effects of the donor-acceptor arrangement on the reactivity of the molecules. Given that donor-sigma-acceptor molecules have recently been found to show self-assembly behavior and macromolecular properties linked to their unusual structure, the current analysis encourages further consideration of the systems in advanced materials applications.     

Chiral periodic mesoporous organosilicates based on axially chiral monomers: transmission of chirality in the solid state

Chiral mesoporous materials have been prepared with purely organic monomers employing an enantiomerically pure biphenyl bis-siloxane as a dopant along with simple 4,4'-bis(triethoxysilyl)biphenyl as the bulk material. Analysis of these materials by CD spectroscopy indicates the formation of new chiral aggregates in the solid state consistent with charge delocalization from adjacent aryl rings in close contact. These aggregates are only observed when the biphenyl and enantiomerically pure biaryl are both present. The red-shift resulting of the CD signal resulting from these interactions is modeled computationally using time-dependent DFT calculations.