A new semifield of order 2

In [G. Lunardon, Semifields and linear sets of PG(1,q^t), Quad. Mat., Dept. Math., Seconda Univ. Napoli, Caserta (in press)], G. Lunardon has exhibited a construction method yielding a theoretical family of semifields of order q²ⁿ,n>1 and n odd, with left nucleus F_qⁿ, middle and right nuclei both F_q² and center F_q. When n=3 this method gives an alternative construction of a family of semifields described in [N.L. Johnson, G. Marino, O. Polverino, R. Trombetti, On a generalization of cyclic semifields, J. Algebraic Combin. 26 (2009), 1-34], which generalizes the family of cyclic semifields obtained by Jha and Johnson in [V. Jha, N.L. Johnson, Translation planes of large dimension admitting non-solvable groups, J. Geom. 45 (1992), 87-104]. For n>3, no example of a semifield belonging to this family is known.In this paper we first prove that, when n>3, any semifield belonging to the family introduced in the second work cited above is not isotopic to any semifield of the family constructed in the former. Then we construct, with the aid of a computer, a semifield of order 2¹⁰ belonging to the family introduced by Lunardon, which turns out to be non-isotopic to any other known semifield.     

Shear banding in biphasic liquid-liquid systems

In this Letter, we present the first systematic report of shear-induced banding in microconfined biphasic liquid-liquid systems, i.e., formation of alternating regions of high and low volume fraction of dispersed-phase droplets in a parallel plate flow cell. Such a flow-driven, gap-dependent phenomenon is only observed at low values of the viscosity ratio between the dispersed and the continuous phase, and in a given range of the applied shear rate. Based on rheological measurements, band formation is found to be associated with a viscosity decrease as compared to the homogeneous, structureless case, thus showing that system microstructure is somehow evolving towards reduced viscous dissipation under shear flow.     

Violation of the Cauchy-Schwarz inequality in the macroscopic regime

We have observed a violation of the Cauchy-Schwarz inequality in the macroscopic regime by more than 8 standard deviations. The violation has been obtained while filtering out only the low-frequency noise of the quantum-correlated beams that results from the technical noise of the laser used to generate them. We use bright intensity-difference squeezed beams produced by four-wave mixing as the source of the correlated fields. We also demonstrate that squeezing does not necessarily imply a violation of the Cauchy-Schwarz inequality.     

Reflectance and ultraviolet spectroscopy: predicting the relative growth of Saccharomyces cerevisiae in pine biomass

Ultrasound treatment favors enzymatic attack on vegetal materials and influences biological activity. The objective of this study was to develop substrates for Saccharomyces cerevisiae based on the hydrothermal treatment and ultrasound treatment of pine needle biomass. The samples subjected to ultrasound treatment at 550?°C and 650?°C showed higher reflectance bands at around 200?nm after 80?min of ultrasound treatment and lower band gap energies associated with lower IC₃₀ values. The hydrothermal treatment with 100?min of ultrasound treatment generated more promising materials for the use of the substrates with the eukaryotic model S. cerevisiae.     

Solid-state structures and conformational studies of four 1,2,3,4-tetrahydroacridine Alzheimer's disease therapeutics

The solid-state structures of four 1,2,3,4-tetrahydroacridines [tacrine hydrochloride monohydrate (1), 7-methoxytacrine hydrochloride monohydrate (2), velnacrine hydrogenmaleate (3) and suronacrine hydrogenmaleate (4)] were determined from single-crystal X-ray diffraction analysis. (1): monoclinic,P2₁/n, a=8.778(1),b=8.521(1),c=17.603(2)Å, =101.34(1)°. (2): monoclinic,C2/c, a=12.326(7),b=18.050(9),c=13.822(8)Å, =113.70(4)°. (3): triclinic, ,a=7.349(2),b=9.417(3),c=12.557(4)Å, =109.62(2), =98.12(2), =101.18(2)°. (4): monoclinic,P2₁/n, a=8.513(6),b=18.74(1),c=13.401(6)Å, =91.21(5)°. FinalR factors for compounds(1)–(4) are 0.047, 0.057, 0.057, 0.11, respectively. The overall arrangement of the common aminotetrahydroacridine skeleton looks similar in all derivatives. However, whereas enantiomerization of the unsubstituted cyclohexenyl rings occurs in (1) and (2), onlyquasi-axially hydroxyl substituted diastereomers are found for (3) and (4). This is presumably due to the different propensities for hydrogen bonding of axially vs. equatorially disposed hydroxyl groups with the hydrogenmaleate anions. Empirical and semiempirical calculations were performed to examine the conformational behavior of the four compounds, bothin vacuo and in solution.     

Structural studies on Ba(II) adducts of the cytosine nucleobase and its derivative 1-Methylcytosine*

Abstract

The use of the cytosine nucleobase or its 1-Methylcytosine derivative as ligands toward barium(II) cations led to the formation of three compounds, {[Ba(1-Mecyt)(H₂O)X₂]}_n [X=Cl (1), Br (2)], and {[Ba(cyt)₂(H₂O)(ClO₄)₂]}_n (3). Depending on the ligand and the counterion employed, 1–3 exhibit different architectures, which serve as a playground to study how the methyl substitution, together with the nature of the counterion are both significant in the self-assembling process of such species. The effect of the nature and size of the alkaline-earth metal ion on the final structural motif is also evident when comparing these structures with parent complexes of the Ca(II) ion.