New possibilities for studying nucleon resonances in the production of π + π − pairs by polarized electrons on an unpolarized proton

The difference of the cross sections for double charged-pion production in the scattering of opposite-helicity electrons on an unpolarized proton is evaluated within the phenomenological model developed previously. The electromagnetic nucleon-resonance form factors and the parameters of nonresonance processes were taken from a fit to the latest data of the CLAS Collaboration on double charged-pion electroproduction. The effect of the longitudinal excitations of the P ₁₁(1440) and D ₁₃(1520) states on the difference of the helicity components of the cross section is studied. The sensitivity of this observable to the nucleon-resonance contribution opens the possibility of employing it both in extracting the Coulomb form factors and in seeking new baryon states. Signals from one of these states were possibly observed in the latest data of the CLAS Collaboration.     

A new procedure for analysis of single-mode-fiber far-field data

A new procedure for analysis of far-field data on single-mode fibers is proposed; it allows one to obtain mode field diameters with reproducibility of ±0.05 μm or better and to reconstruct reliably and unambiguously the refractive-index profile even for dispersion-modified fibers with moderate requirements on dynamic range of the measurements.     

Mesoscopic correlation of supramolecular chirality in one-dimensional hydrogen-bonded assemblies

The ordering of 4-[trans-2-(pyrid-4-yl-vinyl)] benzoic acid, a two-dimensional chiral species, was studied by scanning tunneling microscopy at noble metal surfaces. Homochiral molecules self-assemble in supramolecular chiral hydrogen-bonded twin chains, which order in nanogratings where the supramolecular chirality is strictly correlated over the entire microm domains without intimate molecular contact. Model simulations indicate that the underlying mesoscopic chiral resolution is associated with twin chains acting as chiroselective templates for transient molecular attachment, which process mediates the gratings' evolution.     

Separation by cation-exchange high-performance liquid chromatography of three forms of Chinese hamster ovary cell-derived recombinant human interleukin-2

Purified recombinant (r) interleukin 2 (IL-2) produced by a transformed Chinese hamster ovary cell line shows a single peak when analysed by reversed-phase high-performance liquid chromatography, but it can be resolved into three forms by sodium dodecyl sulphate polyacrylamide gel electrophoresis. These three forms were successfully isolated by narrow-bore ion-exchange chromatography through optimization of the elution conditions. The addition of n-propanol as an organic modifier to the mobile phase proved to be essential for the recovery of the protein from the column in a yield of 90% or better based on protein quantification and biological activity determination. This chromatographic method was used for the purification of these three rIL-2 forms which represent variable glycosylation of a single polypeptide chain. A comparison of the biological activities using the murine CTLL-2 cell proliferation assay showed that the specific activities of the three forms are similar.     

Statistical analysis of intrinsic joint losses in mismatched multimode fibres

The effects of manufacturing variations in geometrical and optical parameters of multimode fibres on intrinsic joint losses are studied by means of a statistical approach. The analysis is performed considering different real conditions of propagation and statistical distributions of fibre parameters. The effects of a cascade of joints and of different jointing techniques are also studied. The calculations are carried out using the real tolerances recommended by the standardization organizations, through a simulation of some 500 000 joints. Except for the case of mismatch of numerical aperture (whose tolerance is relatively large) a mean joint loss of 0.07–0.2 dB and a 98th percentile of joint loss of 0.4–0.7 dB is obtained, depending on the statistical distribution of fibre parameters.     

Scattering in optical fibres: analysis of mode degeneration

Mode degeneration and mode conversion in multimode optical fibres are the main subjects of this work. In particular it is shown how fluctuations of the core shape can cause a rapid degeneration among the modes with the same azimuthal mode number. This allows a rigorous single variable approach to the second problem obtaining evident simplifications. The formalism proposed is applied to the study of mode distribution in the general case of microbending, of core-radius fluctuations in fibres with power law profiles and for simultaneous presence of microbending and ellipticity in parabolic fibres with differential mode attenuation.     

Carbon Nanostructured Screen‐printed Electrodes Modified with CuO/Glucose Oxidase/Maltase/SiO2 Composite Film for Maltose Determination

A sensitive voltammetric method was developed to determine maltose in beverage products using a carbon nanostructured screen‐printed electrode modified with CuO/glucose oxidase/maltase/SiO₂ biocomposite film. Adding CuO particles was done to possess catalytic activity toward hydrogen peroxide. Electrode modified by glucose oxidase and maltase shows a good response to maltose. A well‐defined reduction peak was registered at the potential of ?0.55 V (vs. Ag/AgCl) which intensity increases linearly with the concentration of maltose ranging from 0.01 to 0.1 mmol L^?1. The calculated limit of detection was 0.005 mmol L^?1. Tested on the beer samples, the developed CuO/glucose oxidase/maltase/SiO₂ biocomposite film covered carbon nanostructured screen‐printed electrode is showed to be a prospective sensitive element of the third generation biosensor for maltose.     

Preservation of vitamins content in Cuccìa using an innovative method of processing

Abstract

Cuccìa is a traditional Sicilian food prepared by boiling whole durum wheat kernels, in water, for many hours. This process destroys the vitamins E and B contents of crude kernels. It was rated a method to prepare the Cuccìa, preserving the vitamin content. Four varieties of durum wheat were processed comparing the traditional cooking method (TR-boiling for 5/6?hours), and an innovative one (IN-grains scarification, germination, and cooking at 50?°C for 2?hours). On soups obtained the content of biotin, niacin and α-amylase activity were determined. ANOVA showed the cooking method influences biotin and niacin content having values from 0.56 and 0.72?ng ml^?1 (raw grain) and values close to 0 (TR), while only a 10% decrease (IN) respectively for both vitamins. On the contrary, α-amylase activity was reduced with IN method. The IN method combined with ancient grains, produces the soup with a good vitamin B amount.     

Secondary metabolites of Tilia tomentosa Moench inflorescences collected in Central Italy: chemotaxonomy relevance and phytochemical rationale of traditional use

Abstract

In this paper, the phytochemical analysis on the inflorescences (flowers and bracts) of a sample of Tilia tomentosa collected from an isolated population in Central Italy, was reported for the first time. Thirteen compounds (oleanolic acid, maslinic acid, apigenin, luteolin, kaempferol, quercetin, kaempferol-3-O-glucoside, quercetin-3-O-glucoside, rutin, tiliroside, ellagic acid, shikimic acid and quinic acid), belonging to several different classes of natural products, were identified on the basis of spectroscopic and spectrometric analysis. This sample was found to be mainly composed by flavonoids, followed by organic acids and pentacyclic triterpenes. The chemosystematic aspects of the identified components were also discussed, together with their pharmacologic relevance with respect to the traditional medicinal uses of this plant material.