Dai villaggi operai agli "ecovillaggi" - Linee guida per il recupero secondo il modello di cohousing

La ricerca ha come obiettivo la stesura di linee guida per il recupero dei villaggi operai ottocenteschi e per la loro riconversione secondo il modello del cohousing, che presenta delle forti analogie con la tipologia insediativa analizzata. L’idea di questa ricerca è nata, oltre che dalle somiglianze tra questi tipi di insediamenti abitativi, dalla considerazione che non tutti i villaggi operai rimasti possono essere musealizzati; inoltre,la tendenza in atto in campo edilizio mira al recupero del patrimonio esistente, per evitare l’ulteriore uso di suolo

Oil palm in vitro regeneration: microdensitometric analysis during reproduction and development

An extensive microdensitometric analysis was performed in oil palm Elaeis guineensis Jacq. during the establishment of a new embryogenic culture, on new regenerated plants at different times, and finally on seedlings obtained from adult regenerated normal and abnormal plants. Moreover nuclear DNA content was determined as well during the progression of meiosis. A variable loss of DNA content/nucleus in regenerated plants was demonstrated, in some cases very severe, depending mainly on the in vitro stationing of explants before the regeneration induction; DNA variation, but to less extent, was recorded also in seedlings from adult mother plants of the same genotype, in vivo and in vitro propagated. Considering normal and abnormal regenerated plants, DNA content variations did not seem to be necessarily connected to the abnormal phenotype. In addition stable and different variants in genome size could be obtained from in vitro culture of the same explant. Changes in the values of nuclear DNA content were determined during the meiotic prophase, confirming DNA extrusion processes also observed in other plant systems in vivo. Indeed the regeneration process may induce a quantitative DNA modulation/loss per cell in the regenerated plants but progressively DNA sequences should be regained before completion of the meiotic process. This information points to mechanisms of somaclonal variation

Molecular aspects of zygotic embryogenesis in sunflower (Helianthus annuus L.): correlation of positive histone marks with HaWUS expression and putative link HaWUS/HaL1L

Main conclusion The link HaWUS/HaL1L, the opposite transcriptional behavior, and the decrease/increase in positive histone marks bond to both genes suggest an inhibitory effect of WUS on HaL1L in sunflower zygotic embryos. In Arabidopsis, a group of transcription factors implicated in the earliest events of embryogenesis is the WUSCHELRELATED HOMEOBOX (WOX) protein family including WUSCHEL (WUS) and other 14 WOX protein, some of which contain a conserved WUS-box domain in addition to the homeodomain. WUS transcripts appear very early in embryogenesis, at the 16-cell embryo stage, but gradually become restricted to the center of the developing shoot apical meristem (SAM) primordium and continues to be expressed in cells of the niche/organizing center of SAM and floral meristems to maintain stem cell population. Moreover, WUS has decisive roles in the embryonic program presumably promoting the vegetative-to-embryonic transition and/or maintaining the identity of the embryonic stem cells. However, data on the direct interaction between WUS and key genes for seed development (as LEC1 and L1L) are not collected. The novelty of this report consists in the characterization of Helianthus annuus WUS (HaWUS) gene and in its analysis regarding the pattern of the methylated lysine 4 (K4) of the Histone H3 and of the acetylated histone H3 during the zygotic embryo development. Also, a parallel investigation was performed for HaL1L gene since two copies of the WUS-binding site (WUSATA), previously identified on HaL1L nucleotide sequence, were able to be bound by the HaWUS recombinant protein suggesting a not described effect of HaWUS on HaL1L transcription

Anomalous Angular Dependence of the Dynamic Structure Factor near Bragg Reflections: Graphite

The electron energy-loss function of graphite is studied for momentum transfers q beyond the first Brillouin zone. We find that near Bragg reflections the spectra can change drastically for very small variations in q. The effect is investigated by means of first principle calculations in the random phase approximation and confirmed by inelastic x-ray scattering measurements of the dynamic structure factor S(q,\omega). We demonstrate that this effect is governed by crystal local field effects and the stacking of graphite. It is traced back to a strong coupling between excitations at small and large momentum transfers

Phytoremediation for improving the quality of effluents from a conventional tannery wastewater treatment plant

In the present study, the quality of effluents from a conventional wastewater treatment plant in Italy has been analyzed. Residual level of contamination by 4-nnonylphenol, mono- and di-ethoxylated nonylphenols has been recorded in the effluents that resulted to be also phytotoxic and genotoxic. The possibility of exploiting phytoremediation as a sustainable tertiary treatment for the depletion of the priority pollutants and for the reduction in the residual toxicity has been verified at mesocosm scale. The phyto-based treatment has been performed by the exploitation of Phragmites australis by either a bacterialassisted and not assisted approach. In relation to the bacterial-assisted approach, two new bacterial strains, capable of using the nonylphenols as a sole carbon source, have been isolated. One was identified as a plant growth-promoting rhizobacteria (PGPR) belonging to the Stenotrophomonas species, and the second one was classified as a Sphingobium species strain. Both strains were independently bioaugmented in the P. australis rhizosphere. In relation to the not assisted approach, the phyto-based process determined 87, 70 and 87 % for 4-n-nonylphenol, mono-ethoxylated nonylphenols and di-ethoxylated nonylphenols, respectively. The toxicological assessment of the process evidenced the complete depletion of either the phytotoxicity or the genotoxicity of the treated effluents. With reference to the bacterial-assisted approach, the PGPR Stenotrophomonas species strain resulted to be capable of significantly increasing the efficiency of the phyto-based process in nonylphenol depletion up to 88 % for the 4-n-nonylphenol, 84 % for the mono-ethoxylated nonylphenol and 71 % for the di-ethoxylated nonylphenol

Advanced techniques to investigate the internalization mechanism of TiO2 NPs in the roots grown in a biosolid-amended agricultural soil

Plants play an important role in introducing the engineered nanoparticles (ENPs) into the food chain. The pathway of ENPs uptake from soil, their distribution in the edible plant parts, and their impact in the food production are important issues to be investigated. In the present study, Pisum sativum plants were grown at microcosm scale under medium-term TiO2 NPs exposure, to possibly mime environmental conditions in an agricultural soil amended with biosolids from a wastewater treatment plant in Pisa, Italy. TiO2 NPs were applied as pure rutile, pure anatase and a mixture of both crystalline phases in the biosolid amended-soil. Micro-XRF and μ-XANES from ID21 beamline were used for Ti elemental mapping and crystalline phase identification to indicate a relative distribution/localization of TiO2 crystalline phases within a given cross-section of roots, as well as the possible speciation and preferential crystalline phase uptake in the roots. Titanium in roots showed a main localization in the rizoderma, independently of the crystalline phase. Fewer Ti spots were found localized in the cortex or in vessel, however the roots grown in presence of a mixture of both phases showed a main presence of anatase, suggesting a preferential adsorption and translocation of this crystalline form through the roots. Our data indicated also a reduced translocation of Ti to the aerial part of the plant, confirming the chemical analysis of shoots and roots separately, which showed that Ti concentration was about 40 times lower in the upper part than in the below ground tissues. The TiO2 NPs were characterized on the basis of their size and shape by TEM analysis. Moreover, observations on cell ultrastructure of control and of anatase, rutile and mixture of both crystalline phases treated roots were performed. The root cells of plant grown in the presence of all NPs treatments shared the same alterations of ultrastructure: mitochondria with swollen cristae, nuclei with condensed chromatin, and part of the cytoplasm degraded, probably in consequence of an autophagic process. As detected by μ-XRF and μ-XANES, electron dense prismatic or round profiled particles of about 30-40 nm were observed mainly in form of aggregates in the intercellular spaces or crossing the wall of the cells next to rizoderma and in the cortex cells. Furthermore, the anatase treated cells were mostly damaged in respect to control and rutile treated roots, and more frequently internalized NPs were observed in these samples

Excitons and stacking order in h-BN

The strong excitonic emission at 5.75 eV of hexagonal boron nitride (h-BN) makes this material one of the most promising candidate for light emitting devices in the far ultraviolet (UV). However, single excitons occur only in perfect monocrystals that are extremely hard to synthesize, while regular h-BN samples present a complex emission spectrum with several additional peaks. The microscopic origin of these additional emissions has not yet been understood. In this work we address this problem using an experimental and theoretical approach that combines nanometric resolved cathodoluminescence, high resolution transmission electron microscopy and state of the art theoretical spectroscopy methods. We demonstrate that emission spectra are strongly inhomogeneus within individual flakes and that additional excitons occur at structural deformations, such as faceted plane folds, that lead to local changes of the h-BN stacking order

Polycyclic aromatic hydrocarbon-contaminated soils: bioaugmentation of autochthonous bacteria and toxicological assessment of the bioremediation process by means of Vicia faba L.

Two bacterial strains, Achromobacter sp. (ACH01) and Sphingomonas sp. (SPH01), were isolated from a heavily polycyclic aromatic hydrocarbon (PAH)-contaminated soil (5431.3 ± 102.3 ppm) for their capacity to use a mixture of anthracene, pyrene, phenanthrene and fluorene as sole carbon sources for growth and for the capacity to produce biosurfactants. The two strains were exploited for bioaugmentation in a biopile pilot plant to increase the bioavailability and the degradation of the residual PAH contamination (99.5 ± 7.1 ppm) reached after 9 months of treatment. The denaturing gel gradient electrophoresis (DGGE) profile of the microbial ecology of the soil during the experimentation showed that the bioaugmentation approach was successful in terms of permanence of the two strains in the soil in treatment. The bioaugmentation of the two bacterial isolates positively correlated with the PAH depletion that reached 7.9 ± 2 ppm value in 2 months of treatment. The PAH depletion was assessed by the loss of the phyto-genotoxicity of soil elutriates on the model plant Vicia faba L., toxicological assessment adopted also to determine the minimum length of the decontamination process for obtaining both the depletion of the PAH contamination and the detoxification of the soil at the end of the process. The intermediate phases of the bioremediation process were the most significant in terms of toxicity, inducing genotoxic effects and selective DNA fragmentation in the stem cell niche of the root tip. The selective DNA fragmentation can be related to the selective induction of cell death of mutant stem cells that can compromise offsprings

Linear plasmon dispersion in single-wall carbon nanotubes and the collective excitation spectrum of graphene

We have measured a strictly linear pi-plasmon dispersion along the axis of individualized single wall carbon nanotubes, which is completely different from plasmon dispersions of graphite or bundled single wall carbon nanotubes. Comparative ab initio studies on graphene based systems allow us to reproduce the different dispersions. This suggests that individualized nanotubes provide viable experimental access to collective electronic excitations of graphene, and it validates the use of graphene to understand electronic excitations of carbon nanotubes. In particular, the calculations reveal that local field effects (LFE) cause a mixing of electronic transitions, including the 'Dirac cone', resulting in the observed linear dispersion