188 research outputs found
Ascorbic acid content and senescence in blueberry (Vaccinium corymbosum L.) during storage
Blueberry consumption increases because its health properties linked to antioxidants, easy cultivation and profitability. The ability to preserve fruits in controlled atmosphere (CA) allows extending the marketing calendar. The work evaluates parameters linked to the cellular redox state of blueberry fruits, cv. Brigitta, stored at 0\ub0C at different atmosphere regimes (CA1= 10% CO2, 4% O2 and CA2= 9% CO2, 2% O2, compared to air as control). During storage, quality was assessed by the content of ascorbic acid (AA), antioxidant and index of fruit metabolic status, and of malondialdehyde (MDA), cell membranes oxidative stress and senescence marker; soluble solids content, titratable acidity and dry matter were also determined. Storage in CA increases the blueberries shelf life, particularly at the intermediate times; after 2 months there is a drastic lowering in AA levels and differences among treatments are no longer detectable. Ascorbate is confirmed to be an excellent index of oxidative stress in fruit senescence processes. In control, along with the AA decrease, there is a higher MDA content, in particular up to the intermediate dates. CA2 proves to be the most suitable atmosphere for delaying the senescence process. Titratable acidity and soluble solids remain constant in all samples throughout storage
Variation of Anthocyanin Content and Profile Throughout Fruit Development and Ripening of Highbush Blueberry Cultivars Grown at Two Different Altitudes
Blueberry (Vaccinium corymbosum L.) is a widely consumed fruit and a rich source of bioactive compounds, namely, the polyphenol class of anthocyanins. Little information is available about the influence of internal (genetic and developmental) and external (environmental) factors on the levels of phenolic metabolites in blueberry fruit. In light of this consideration, total polyphenolic and flavonoid content, anthocyanin accumulation and composition were evaluated in cv. \u201cDuke\u201d and \u201cBrigitta\u201d grown at two different altitudes in Valtellina, a valley of the Alps in Northern Italy. During berry ripening, there is a developmentally coordinated shift from cyanidin-type, di-substituted anthocyanins toward delphinidin-based, tri-substituted pigments. At the lower altitude location, higher temperatures, not exceeding optimum, resulted in a more quickly berry developmental pattern and in higher anthocyanin concentrations in the early phases of ripening. At later stages of ripening, berries of both cultivars at higher altitude compensate for these initial temperature effects, and no differences were recorded in ripe fruit grown in the two locations. We conclude that anthocyanin accumulation is strongly regulated by development and genotype, and the environmental factors, associated to the altitude gradient, exert in the trial conditions only a fine-tuning influence. Fruits reach the full-ripening stage simultaneously at both sites because the initial gap in pigment levels is counterbalanced at the higher altitude by a faster rate of accumulation at later phases of the ripening process
Evaluation of borage extracts as potential biostimulant using a phenomic, agronomic, physiological and biochemical approach
Biostimulants are substances able to improve water and nutrient use efficiency and counteract stress factors by enhancing primary and secondary metabolism. Premise of the work was to exploit raw extracts from leaves (LE) or flowers (FE) of Borago officinalis L., to enhance yield and quality of Lactuca sativa ‘Longifolia,’ and to set up a protocol to assess their effects. To this aim, an integrated study on agronomic, physiological and biochemical aspects, including also a phenomic approach, has been adopted. Extracts were diluted to 1 or 10 mL L–1, sprayed onto lettuce plants at the middle of the growing cycle and 1 day before harvest. Control plants were treated with water. Non-destructive analyses were conducted to assess the effect of extracts on biomass with an innovative imaging technique, and on leaf photosynthetic efficiency (chlorophyll a fluorescence and leaf gas exchanges). At harvest, the levels of ethylene, photosynthetic pigments, nitrate, and primary (sucrose and total sugars) and secondary (total phenols and flavonoids) metabolites, including the activity and levels of phenylalanine ammonia lyase (PAL) were assessed. Moreover, a preliminary study of the effects during postharvest was performed. Borage extracts enhanced the primary metabolism by increasing leaf pigments and photosynthetic activity. Plant fresh weight increased upon treatments with 10 mL L–1 doses, as correctly estimated by multi-view angles images. Chlorophyll a fluorescence data showed that FEs were able to increase the number of active reaction centers per cross section; a similar trend was observed for the performance index. Ethylene was three-fold lower in FEs treatments. Nitrate and sugar levels did not change in response to the different treatments. Total flavonoids and phenols, as well as the total protein levels, the in vitro PAL specific activity, and the levels of PAL-like polypeptides were increased by all borage extracts, with particular regard to FEs. FEs also proved efficient in preventing degradation and inducing an increase in photosynthetic pigments during storage. In conclusion, borage extracts, with particular regard to the flower ones, appear to indeed exert biostimulant effects on lettuce; future work will be required to further investigate on their efficacy in different conditions and/or species
Growth and Characterization of Cu2Zn1-xFexSnS4 Thin Films for Photovoltaic Applications.
Photovoltaics is a promising technology to produce sustainable energy, thanks to the high amount of energy emitted by the sun. One way of having solar cells with low production costs is to apply thin-film technology and with earth-abundant raw materials. A keen interest is arising in kesterite compounds, which are chalcogenides composed of abundant and non-toxic elements. They have already achieved excellent performance at the laboratory level. Here, we report the synthesis and characterization of mixed chalcogenides based on copper, zinc, iron, and tin. Solutions have been studied with different zinc and iron ratios. The distortion of the elementary cell of kesterite increases with the addition of iron until a phase transition to stannite occurs. The process of synthesis and deposition proposed herein is cheap and straightforward, based on the sol-gel technique. These thin films are particularly attractive for use in cheap and easily processable solar cells. The synthesized layers have been characterized by X-ray diffraction, UV-Vis absorption, and Raman, X-ray photoelectron, and energy-dispersive X-ray spectroscopy measurements
Transcatheter closure of pfo and asd: Multimodality imaging for patient selection and perioperative guidance
Transcatheter closure of patent foramen ovale (PFO) and secundum type atrial septal defect (ASD) are common transcatheter procedures. Although they share many technical details, these procedures are targeting two different clinical indications. PFO closure is usually considered to prevent recurrent embolic stroke/systemic arterial embolization, ASD closure is indicated in patients with large left-to-right shunt, right ventricular volume overload, and normal pulmonary vascular resistance. Multimodality imaging plays a key role for patient selection, periprocedural monitoring, and follow-up surveillance. In addition to routine cardiovascular examinations, advanced neuroimag-ing studies, transcranial-Doppler, and interventional transesophageal echocardiography/intracardiac echocardiography are now increasingly used to deliver safely and effectively such procedures. Long-standing collaboration between interventional cardiologist, neuroradiologist, and cardiac imager is essential and it requires a standardized approach to image acquisition and interpretation. Peripro-cedural monitoring should be performed by experienced operators with deep understanding of technical details of transcatheter intervention. This review summarizes the specific role of different imaging modalities for PFO and ASD transcatheter closure, describing important pre-procedural and intra-procedural details and providing examples of procedural pitfall and complications
Effect of temperature and cut size on the volatile organic compound profile, and expression of Chorismate synthase in fresh-cut melon
The postharvest quality of fresh-cut melon is strongly affected by storage conditions to which it is subjected. During postharvest, fruit undergoes several stresses and its physiology is similar to that in senescent tissues. This affects both its biochemistry and the expression of genes involved in secondary metabolite biosynthesis. Volatile organic compounds (VOCs) have been used previously to assess quality of fresh cut melon as they reflect changes in flavor and also changes in overall metabolism. Chorismate synthase (CS) is a key enzyme in the shikimate pathway and catalyzes the formation of chorismate, which is the precursor of numerous aromatic compounds in plants. In this work the effects of different storage temperatures and cut-sizes were studied, with the aim of identifying effects on flavor through changes in VOCs, and molecular responses of the CmCS gene to different postharvest conditions. Melon (Cucumis melo L. 'Macigno') fruits were harvested at a fully ripened commercial stage, were washed in a chlorine water solution, and the mesocarp (pulp) was cut in cube-shaped portions; two sizes were chosen, 1×1 and 3×2 cm. Melon cubes were then stored at 20 or 4°C. VOCs were assessed in the 3×2 cut size at both temperatures and showed clear changes during storage. A subset of VOCs were shown to correlate negatively with storage time and temperature and from these, specific compounds can be identified that act as markers for an overall change in VOC profiles. CmCS was more affected by temperature, showing decreased levels of expression during storage at 20°C with respect to harvest and to cold storage. On the other hand, cut-size did not result in changes in its expression in 3×2 cut size
A Review of Sociological Issues in Fire Safety Regulation
This paper presents an overview of contemporary sociological issues in fire safety. The most obviously social aspects of fire safety—those that relate to the socioeconomic distribution of fire casualties and damage—are discussed first. The means that society uses to mitigate fire risks through regulation are treated next; focusing on the shift towards fire engineered solutions and the particular challenges this poses for the social distribution and communication of fire safety knowledge and expertise. Finally, the social construction of fire safety knowledge is discussed, raising questions about whether the confidence in the application of this knowledge by the full range of participants in the fire safety design and approvals process is always justified, given the specific assumptions involved in both the production of the knowledge and its extension to applications significantly removed from the original knowledge production; and the requisite competence that is therefore needed to apply this knowledge. The overarching objective is to argue that the fire safety professions ought to be more reflexive and informed about the nature of the knowledge and expertise that they develop and apply, and to suggest that fire safety scientists and engineers ought to actively collaborate with social scientists in research designed to study the way people interact with fire safety technology
- …