Monitoring the production yields of vincristine and vinblastine in Catharanthus roseus from somatic embryogenesis. Semiquantitative determination by flow-injection electrospray ionization mass spectrometry

A semiquantitative determination of two bis-indole antitumor alkaloids, vincristine and vinblastine, has been performed by flow-injection electrospray ionization mass spectrometric analysis of the extracts of Catharanthus roseus. Leaves and flowers of two different phenotypes (pink flower and white flower) obtained from somatic embryogenesis were thus examined and compared with the field-grown mother plant. Different amounts of vincristine and vinblastine were detected depending on the examined samples.     

Hypervalent organochalcogenanes as inhibitors of protein tyrosine phosphatases

A series of organochalcogenanes was synthesized and evaluated as protein tyrosine phosphatases (PTPs) inhibitors. The results indicate that organochalcogenanes inactivate the PTPs in a time- and concentration-dependent fashion, most likely through covalent modification of the active site sulfur-moiety by the chalcogen atom. Consequently, organochalcogenanes represent a new class of mechanism-based probes to modulate the PTP-mediated cellular processes.     

Linear viscoelastic analysis of straight and curved thin-walled laminated composite beams

This paper is devoted to study the behavior, in the range of linear viscoelasticity, of shear flexible thin-walled beam members constructed with composite laminated fiber-reinforced plastics. This work appeals to the correspondence principle in order to incorporate in unified model the motion equations of a curved or straight shear-flexible thin-walled beam member developed by the authors, together with the micromechanics and macromechanics of the reinforced plastic panels. Then, the analysis is performed in the Laplace or Carson domains. That is, the expressions describing the micromechanics and macromechanics of a plastic laminated composites and motion equations of the structural member are transformed into the Laplace or Carson domains where the relaxation components of the beam structure (straight or curved) are obtained. The resulting equations are numerically solved by means of finite element approaches defined in the Laplace or Carson domains. The finite element results are adjusted with a polynomial fitting. Then the creep behavior is obtained by means of a numerical technique for the inverse Laplace transform. Predictions of the present methodology are compared with experimental data and other approaches. New studies are performed focusing attention in the flexural–torsional behavior of shear flexible thin-walled straight composite beams as well as for thin-walled curved beams and frames.     

Monitoring of Spirulina Flakes and Powders from Italian Companies

Microalgae and microalgae-derived compounds have great potential as supplements in the human diet and as a source of bioactive products with health benefits. Spirulina (Arthrospira platensis (Nordstedt) Gomont, or Spirulina platensis) belongs to the class of cyanobacteria and has been studied for its numerous health benefits, which include anti-inflammatory properties, among others. This work was aimed at comparing some spirulina products available on the Italian market. The commercial products here analyzed consisted of spirulina cultivated and processed with different approaches. Single-component spirulina products in powder and flake form, free of any type of excipient produced from four different companies operating in the sector, have been analyzed. The macro- and micromorphological examination, and the content of pigments, phycobiliproteins, phenols, and proteins have shown differences regarding the morphology and chemical composition, especially for those classes of particularly unstable compounds such as chlorophylls and carotenoids, suggesting a great influence of both culture conditions and processing methods.     

Identification of the tension force in cables with insulators

Meccanica - The present paper explores two approaches which, based on the measurement of the two first natural frequencies, allow the identification of the tension force in cables with insulators....     

Synthesis,Mechanism Elucidation and Biological Insights of Tellurium(IV)-Containing Heterocycles

Inspired by the synthetic and biological potential of organotellurium substances, a series of five- and six-membered ring organotelluranes containing a Te−O bond were synthesized and characterized. Theoretical calculations elucidated the mechanism for the oxidation-cyclization processes involved in the formation of the heterocycles, consistent with chlorine transfer to hydroxy telluride, followed by a cyclization step with simultaneous formation of the new Te−O bond and deprotonation of the OH group. Moreover, theoretical calculations also indicated anti-diastereoisomers to be major products for two chirality center–containing compounds. Antileishmanial assays against Leishmania amazonensis promastigotes disclosed 1,2λ⁴-oxatellurane LQ50 (IC₅₀=4.1±1.0; SI=12), 1,2λ⁴-oxatellurolane LQ04 (IC₅₀=7.0±1.3; SI=7) and 1,2λ⁴-benzoxatellurole LQ56 (IC₅₀=5.7±0.3; SI=6) as more powerful and more selective compounds than the reference, being up to four times more active. A stability study supported by ¹²⁵Te NMR analyses showed that these heterocycles do not suffer structural modifications in aqueous-organic media or at temperatures up to 65 °C.     

On Rosenhain-Göpel configurations and integrable systems

We give a birational morphism between two types of genus 2 Jacobians in ?¹⁵. One of them is related to an Algebraic Completely Integrable System: the Geodesic Flow on SO(4), metric II (so termed after Adler and van Moerbeke). The other Jacobian is related to a linear system in |4Θ| with 12 base points coming from a Göpel tetrad of 4 translates of the Θ divisor. A correspondence is given on the base spaces so that the Poisson structure of the SO(4) system can be pulled back to the family of Göpel Jacobians.