A pimpinellin monomer and dimer isolated from the roots of Esenbeckia grandiflora

X‐ray diffraction studies carried out on single crystals of the monomeric, viz. 5,6‐di­methoxy‐2H‐furo­[2,3‐h][1]benzo­pyran‐2‐one, C₁₃H₁₀O₅, and dimeric, viz. 5,5′,6,6′‐tetra­methoxy‐3,3′,4,4′‐tetra­hydro‐2H,2′H‐3,3′:4,4′‐bi­(furo­[2,3‐h][1]benzo­pyran)‐2,2′‐dione, C₂₆H₂₀O₁₀, forms of pimpinellin have revealed that, following cyclo­dimerization, the carbonyl groups are head‐to‐head with respect to one another. In the monomer, the heterocyclic ring is planar, but it exhibits a twisted‐boat conformation in the dimer. Both the monomer and the dimer interact through C—H⋯O interactions.     

Strength vs. toughness optimization of microstructured composites

Aim of this paper is to present a new fractal approach linking the macroscopic mechanical properties of micro- and nano-structured materials with the main parameters: composition, grain size and structural dimension, as well as contiguity and mean free path. Assuming the key role played by the interfaces, the proposed fractal energy approach unifies the influences of all the above parameters, through the introduction of a fractal structural parameter (FSP), which represents an extension of the Gurland’s structural parameter. This modeling approach is assessed through an extensive comparison with experimental data on poly crystalline diamond (PCD) and WC–Co alloys. The results clearly show that the theoretical fractal predictions are in a fairly good agreement with the experiments on both hardness and toughness. This new synthetic parameter is thus proposed to investigate, design and optimize new micro- and nano-grained materials. Eventually, FSP-based optimization maps are developed, that allow to design new materials with high hardness and toughness.     

Nitric oxide and singlet oxygen photo-generation by light irradiation in the phototherapeutic window of a nitrosyl ruthenium conjugated with a phthalocyanine rare earth complex

The photochemical, photophysical and photobiological studies of a mixture containing cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] (H₂-dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) and Na₄[Tb(TsPc)(acac)] (TsPc = tetrasulfonated phthalocyanines; acac = acetylacetone), a system capable of improving photodynamic therapy (PDT), were accomplished. cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] was obtained from cis-[Ru(H₂-dcbpy)₂Cl₂]·2H₂O, whereas Na₄[Tb(TsPc)(acac)] was obtained by reacting phthalocyanine with terbium acetylacetonate. The UV–Vis spectrum of cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] displays a band in the region of 305 nm (λ_max in 0.1 mol L⁻¹ HCl)(π–π*) and a shoulder at 323 nm (MLCT), while the UV–Vis spectrum of Na₄[Tb(TsPc)(acac)] presents the typical phthalocyanine bands at 342 nm (Soret λ_max in H₂O) and 642, 682 (Q bands). The cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] FTIR spectrum displays a band at 1932 cm⁻¹ (Ru–NO⁺). The cyclic voltammogram of the cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)] complex in aqueous solution presented peaks at E = 0.10 V (NO^+/0) and E = −0.50 V (NO^0/−) versus Ag/AgCl. The NO concentration and ¹O₂ quantum yield for light irradiation in the λ > 550 nm region were measured as [NO] = 1.21 ± 0.14 μmol L⁻¹ and ø_OS = 0.41, respectively. The amount of released NO seems to be dependent on oxygen concentration, once the NO concentration measured in aerated condition was 1.51 ± 0.11 μmol L⁻¹ The photochemical pathway of the cis-[Ru(H-dcbpy⁻)₂(Cl)(NO)]/Na₄[Tb(TsPc)(acac)] mixture could be attributed to a photoinduced electron transfer process. The cytotoxic assays of cis-[Ru(H-dcbpy^-)₂(Cl)(NO)] and of the mixture carried out with B16F10 cells show a decrease in cell viability to 80% in the dark and to 20% under light irradiation. Our results document that the simultaneous production of NO and ¹O₂ could improve PDT and be useful in cancer treatment.     

New evolution PDEs with many isochronous solutions

Certain nonlinear evolution PDEs in 1+1 variables (time and space) are identified, featuring a positive parameter ω and evolving, for a large class of initial data, periodically with the fixed period T=2π/ω (or perhaps with p a small integer). They are autonomous (i.e., they do not feature any explicit dependence on the time variable), but they generally (although not quite all of them) depend explicitly on the space variable hence are not translation-invariant. They are integrable, having been obtained by applying an appropriate change of dependent and independent variables to certain nonlinear evolution PDEs whose integrable character has been recently ascertained. Solutions of some of these PDEs are exhibited.     

NMR,RP-HPLC-PDA-ESI-MSn,and RP-HPLC-FD Characterization of Green and Oolong Teas (Camellia sinensis L.)

Untargeted (NMR) and targeted (RP-HPLC-PDA-ESI-MSⁿ, RP-HPLC-FD) analytical methodologies were used to determine the bioactive components of 19 tea samples, characterized by different production processes (common tea and GABA tea), degrees of fermentation (green and oolong teas), and harvesting season (autumn and spring). The combination of NMR data and a multivariate statistical approach led to a statistical model able to discriminate between GABA and non-GABA teas and green and oolong teas. Targeted analyses showed that green and GABA green teas had similar polyphenol and caffeine contents, but the GABA level was higher in GABA green teas than in regular green tea samples. GABA oolong teas showed lower contents of polyphenols, caffeine, and amino acids, and a higher content of GABA, in comparison with non-GABA oolong teas. In conclusion, the results of this study suggest that the healthy properties of teas, especially GABA teas, have to be evaluated via comprehensive metabolic profiling rather than only the GABA content.     

The peculiar (monic) polynomials,the zeros of which equal their coefficients

We evaluate the number of complex monic polynomials, of arbitrary degree N, the zeros of which are equal to their coefficients. In the following, we call polynomials with this property peculiar polynomials. We further show that the problem of determining the peculiar polynomials of degree N simplifies when any of the coefficients is either 0 or 1. We proceed to estimate the numbers of peculiar polynomials of degree N having one coefficient zero, or one coefficient equal to one, or neither.     

Comparison of liquid-liquid partition, HS-SPME and static HS GC/MS analysis for the quantification of (-)-linalool in human whole blood samples

The aim of this investigation was to develop a fast and convenient method for the determination of (-)-linalool in human whole blood to facilitate pharmacokinetic studies. Analytical protocols were elaborated for three different GC/MS sampling techniques, i.e., static headspace (s-HS), headspace solid phase micro extraction (HS-SPME), and liquid-liquid partition. In principle, all tested methods were feasible, but s-HS had the greatest benefit because of the easy handling of the blood samples and its short analysis time. For s-HS two different incubation temperatures were tested (40 degrees C and 60 degrees C). The limit of detection was slightly lower when samples were incubated at 60 degrees C, but the same quantitative results were achieved using alpha-terpineol as internal standard. An accurate and sensitive method for the quantification of (-)-linalool in blood samples after either inhalation or percutaneous application, as well as pharmacokinetic data are presented.     

Peracetylated α‐d‐glucopyranosyl fluoride and peracetylated α‐maltosyl fluoride

The X‐ray analyses of 2,3,4,6‐tetra‐O‐acetyl‐α‐d ‐glucopyranosyl fluoride, C₁₄H₁₉FO₉, (I), and the corresponding maltose derivative 2,3,4,6‐tetra‐O‐acetyl‐α‐d ‐glucopyranosyl‐(1→4)‐2,3,6‐tri‐O‐acetyl‐α‐d ‐glucopyranosyl fluoride, C₂₆H₃₅FO₁₇, (II), are reported. These add to the series of published α‐glycosyl halide structures; those of the peracetylated α‐glucosyl chloride [James & Hall (1969). Acta Cryst. A 25 , S196] and bromide [Takai, Watanabe, Hayashi & Watanabe (1976). Bull. Fac. Eng. Hokkaido Univ. 79 , 101–109] have been reported already. In our structures, which have been determined at 140 K, the glycopyranosyl ring appears in a regular ⁴C₁ chair conformation with all the substituents, except for the anomeric fluoride (which adopts an axial orientation), in equatorial positions. The observed bond lengths are consistent with a strong anomeric effect, viz. the C1—O5 (carbohydrate numbering) bond lengths are 1.381 (2) and 1.381 (3) Å in (I) and (II), respectively, both significantly shorter than the C5—O5 bond lengths, viz. 1.448 (2) Å in (I) and 1.444 (3) Å in (II).