Spin-charge decoupling and the photoemission line-shape in one dimensional insulators

The recent advances in angle resolved photoemission techniques allowed the unambiguous experimental confirmation of spin charge decoupling in quasi one dimensional (1D) Mott insulators. This opportunity stimulates a quantitative analysis of the spectral function $A(k,\omega)$ of prototypical one dimensional correlated models. Here we combine Bethe Ansatz results, Lanczos diagonalizations and field theoretical approaches to obtain $A(k,\omega)$ for the 1D Hubbard model as a function of the interaction strength. By introducing a {\it single spinon approximation}, an analytic expression is obtained, which shows the location of the singularities and allows, when supplemented by numerical calculations, to obtain an accurate estimate of the spectral weight distribution in the $(k,\omega)$ plane. Several experimental puzzles on the observed intensities and line-shapes in quasi 1D compounds, like ${\rm SrCuO_2}$, find a natural explanation in this theoretical framework.Comment: 8 pages, submitted to Physical Review

Charge identification of fragments with the emulsion spectrometer of the FOOT experiment

The FOOT (FragmentatiOn Of Target) experiment is an international project designed to carry out the fragmentation cross-sectional measurements relevant for charged particle therapy (CPT), a technique based on the use of charged particle beams for the treatment of deep-seated tumors. The FOOT detector consists of an electronic setup for the identification of Z ≥ 3 fragments and an emulsion spectrometer for Z ≤ 3 fragments. The first data taking was performed in 2019 at the GSI facility (Darmstadt, Germany). In this study, the charge identification of fragments induced by exposing an emulsion detector, embedding a C2 H4 target, to an oxygen ion beam of 200 MeV/n is discussed. The charge identification is based on the controlled fading of nuclear emulsions in order to extend their dynamic range in the ionization response

Performance of the ToF detectors in the foot experiment

The FOOT (FragmentatiOn Of Target) experiment aims to deter- mine the fragmentation cross-sections of nuclei of interest for particle therapy and radioprotection in space. The apparatus is composed of several detectors that allow fragment identification in terms of charge, mass, energy and direction. The frag- ment time of flight (ToF) along a lever arm of ∼2 m is used for particle ID, requiring a resolution below 100ps to achieve a sufficient resolution in the fragment atomic mass identification. The timing performance of the ToF system evaluated with 12C and 16O beams is reviewed in this contribution

Charge identification of fragments with the emulsion spectrometer of the FOOT experiment

The FOOT (FragmentatiOn Of Target) experi- ment is an international project designed to carry out the fragmentation cross-sectional measurements relevant for charged particle therapy (CPT), a technique based on the use of charged particle beams for the treatment of deep-seated tumors. The FOOT detector consists of an electronic setup for the identification of Z >= 3 fragments and an emulsion spectrometer for Z <= 3 fragments. The first data taking was performed in 2019 at the GSI facility(Darmstadt, Germany). In this study, the charge identifi-cation of fragments induced by exposing an emulsion detector, embedding a C2H4 target, to an oxygen ion beam of 200 MeV/n is discussed. The charge identifica-tion is based on the controlled fading of nuclear emulsions in order to extend their dynamic range in the ionization response

Measuring the Impact of Nuclear Interaction in Particle Therapy and in Radio Protection in Space: the FOOT Experiment

In Charged Particle Therapy (PT) proton or 12C beams are used to treat deep-seated solid tumors exploiting the advantageous characteristics of charged particles energy deposition in matter. For such projectiles, the maximum of the dose is released at the end of the beam range, in the Bragg peak region, where the tumour is located. However, the nuclear interactions of the beam nuclei with the patient tissues can induce the fragmentation of projectiles and/or target nuclei and needs to be carefully taken into account when planning the treatment. In proton treatments, the target fragmentation produces low energy, short range fragments along all the beam path, that deposit a non-negligible dose especially in the first crossed tissues. On the other hand, in treatments performed using 12C, or other (4He or 16O) ions of interest, the main concern is related to the production of long range fragments that can release their dose in the healthy tissues beyond the Bragg peak. Understanding nuclear fragmentation processes is of interest also for radiation protection in human space flight applications, in view of deep space missions. In particular 4He and high-energy charged particles, mainly 12C, 16O, 28Si and 56Fe, provide the main source of absorbed dose in astronauts outside the atmosphere. The nuclear fragmentation properties of the materials used to build the spacecrafts need to be known with high accuracy in order to optimise the shielding against the space radiation. The study of the impact of these processes, which is of interest both for PT and space radioprotection applications, suffers at present from the limited experimental precision achieved on the relevant nuclear cross sections that compromise the reliability of the available computational models. The FOOT (FragmentatiOn Of Target) collaboration, composed of researchers from France, Germany, Italy and Japan, designed an experiment to study these nuclear processes and measure the corresponding fragmentation cross sections. In this work we discuss the physics motivations of FOOT, describing in detail the present detector design and the expected performances, coming from the optimization studies based on accurate FLUKA MC simulations and preliminary beam test results. The measurements planned will be also presented

Linking early-life NMDAR hypofunction and oxidative stress in schizophrenia pathogenesis.

Molecular, genetic and pathological evidence suggests that deficits in GABAergic parvalbumin-positive interneurons contribute to schizophrenia pathophysiology through alterations in the brain's excitation-inhibition balance that result in impaired behaviour and cognition. Although the factors that trigger these deficits are diverse, there is increasing evidence that they converge on a common pathological hub that involves NMDA receptor hypofunction and oxidative stress. These factors have been separately linked to schizophrenia pathogenesis, but evidence now suggests that they are mechanistically interdependent and contribute to a common schizophrenia-associated pathology

Valorisation of Ginger and Turmeric Peels as Source of Natural Antioxidants

The antioxidant activity of ginger and turmeric powders derived from freeze-dried rhizomes and peels as well as commercial spices has been evaluated by two spectrophotometric assays based on electron transfer such as DPPH and FRAP. The phenolic characterization has been also carried out by detecting total polyphenols through Folin-Ciocalteu method and HPLC analyzing 6-gingerol and curcumin. Ginger and turmeric peels showed greater antioxidant activity than commercial powders because of their higher phenolic yields. Hence, ginger and turmeric peels can be considered a rich source of phytochemicals which contribute to the antioxidant effects of these agro-food wastes

Water extraction: an ecofriendly strategy to recover antioxidants from ginger and turmeric peels

Messa a punto di un processo di estrazione in acqua per recuperare antiossidanti dalle bucce di zenzero e curcum

Effect of beta-cyclodextrin addition on quality of precooked vacuum packed potatoes

The usefulness of b-cyclodextrin (b-CD) in enhancing the food and nutritional quality of precooked potatoes was studied. After blanching, potato slices were cooled. This was followed by dipping in solutions containing b-CD, ascorbic and citric acids, either alone or in combination with b-CD, and vacuum packaging in pouches. The potatoes were pasteurised/precooked and cooled. These samples were then analyzed for colour parameters, microbial count, Resistant Starch (RS) concentration, fat content after a frying test immediately and after 7, 14 and 28 days of storage at 4 \ub0C. Results showed that dipping with b-CD gave the lightest colour (DL*) and a more attractive appearance.nHowever, growth of aerobic mesophilic bacteria was observed in samples dipping in solutions with b-CD alone. From the nutritional point of view, the effect of b-CD on the RS content of potatoes may be related to storage time

Evaluation of the antioxidant activity and oxidative stability in ginger- and turmeric-enriched soybean oils

The food industry is currently moving towards replacing synthetic additives such as TBHQ, BHA, and BHT with natural antioxidants to prevent the lipid oxidation in oils and fats. In this study, the commercial and freeze-dried powders of ginger and turmeric rhizomes and peels were added to the soybean oil at the concentration of 10% (w/w). After that, the exhaustive powders were subjected to other two recovery cycles. The antioxidant activity and oxidative stability of ginger- and turmeric-enriched soybean oils were evaluated respectively by spectrophotometric and RANCIMAT methods. The phenolic characterization has been also carried out by detecting total polyphenols through Folin-Ciocalteu assay and HPLC analysing 6-gingerol, 6-shogaol and curcumin. Based on the correlation studies, the antioxidant activity as well as oxidative stability, which non-linearly decreased over cycles, linearly increased with increasing phenolic contents. The soybean oils containing freeze-dried peels achieved the best antioxidant results as a consequence of their enrichment in 6-gingerol and curcumin, the main bioactive compounds of respectively ginger and turmeric. Hence, ginger and turmeric can be proposed as a valid source of natural antioxidants for extending the shelf-life of oils and fats. Moreover, the valorisation of peels is useful to convert these agricultural wastes into value-added products