265 research outputs found
First basin-wide experimental results on N2-fixation in the open Mediterranean Sea.
Mediterranean Sea presents several biogeochemical anomalies compared to the global ocean. Unbalanced N budget, high nitrate/phosphate ratios in subsurface waters and light isotopic signals in particulate and dissolved nitrogen have suggested a relevant occurrence of N2-fixation. This study presents, for the first time, N2-fixation rate measurements in the open Mediterranean Sea on a basin scale during early summer, compared to one site in the North Atlantic. Very low rates (0.052?0.031 nmols N l-1d-1) were observed in all sub-regions of the Mediterranean, unlike the higher values measured in the North Atlantic surface waters (0.300?0.115 nmols N l-1d-1). No evidence of phosphate limitation emerges from this study. Low N2-fixation rates associated to light isotopic composition of PON (from -2.10 to 4.11?) suggest that other light N sources, different from atmospheric N2, fuel the Mediterranean ecosystem
Controlled Microfabrication of High-Aspect-Ratio Structures in Silicon at the Highest Etching Rates: The Role of H2O2 in the Anodic Dissolution of Silicon in Acidic Electrolytes
In this work the authors report on the controlled electrochemical etching of high-aspect-ratio (from 5 to 100) structures in silicon at the highest etching rates (from 3 to 10 µm min−1) at room temperature. This allows silicon microfabrication entering a previously unattainable region where etching of high-aspect-ratio structures (beyond 10) at high etching rate (over 3 µm min−1) was prohibited for both commercial and research technologies. Addition of an oxidant, namely H2O2, to a standard aqueous hydrofluoric (HF) acid electrolyte is used to dramatically change the stoichiometry of the silicon dissolution process under anodic biasing without loss of etching control accuracy at the higher depths (up to 200 µm). The authors show that the presence of H2O2 reduces the valence of the dissolution process to 1, thus rendering the electrochemical etching more effective, and catalyzes the etching rate by opening a more efficient path for silicon dissolution with respect to the well-known Gerischer mechanism, thus increasing the etching speed at both shorter and higher depths
Influence of Lobesia botrana field control on black aspergilli rot and ochratoxin A contamination in grapes.
The grape berry moth Lobesia botrana is a key pest in vineyards in southern Europe. Damage caused by L. botrana larvae may encourage growth of black aspergilli, leading to ochratoxin A (OTA) accumulation in grapes. Field trials were conducted during three grape growing seasons (2005 through 2007) in Apulia, Italy, to evaluate an insecticide control strategy for L. botrana in the vineyard as an indirect method of reducing OTA contamination by reducing black aspergilli on the grapes. In the 2005 field trials, the insecticide treatment controlled attacks by L. botrana larvae and reduced OTA concentrations by up to 66% in the must samples of Negroamaro and Primitivo grape varieties. Significant differences (P < or = 0.05) also were observed in the incidence of black aspergilli. Environmental conditions in 2006 and 2007 resulted in a natural low level of infestation by L. botrana, low levels of OTA in both treated and untreated samples, and no significant differences between treated and nontreated samples. The results of our field study confirm previous reports that L. botrana is an important risk factor for OTA accumulation and are consistent with the hypothesis that controlling L. botrana in vineyards reduces OTA concentrations in grapes
Early surgery versus watchful waiting strategy for infantile abdominoscrotal hydrocele
Background: Infantile abdominoscrotal hydrocele is generally managed with early surgery. However, whether these patients actually benefit from an initial watchful waiting strategy is yet to be determined. Methods: This single-center, comparative observational analysis included 36 consecutive patients (9 bilateral cases) diagnosed between January 1998 and December 2019. Initial 16 patients (21 lesions) underwent surgical repair shortly after diagnosis (Group A) at a mean (SD) age of 8 (4) months. Remaining 20 patients (24 lesions) underwent initial nonoperative management (Group B). Overall follow-up was 82.74 (63.84) months. Results: Six lesions of Group B spontaneously regressed at a mean age of 23.8 (7.8) months. Remaining 18 hydroceles underwent surgical management at a mean age of 18.7 (12.6) months. Early postoperative morbidity was high (43%) in both groups (Clavien-Dindo grade I-II). During follow-up, there were 1 recurrent hydrocele and 1 testicular atrophy, both events occurring in Group A patients. Group B patients required a higher need for concomitant ipsilateral orchidopexy (61% versus 14%; p = 0.001), and developed a higher rate of ipsilateral inguinal hernia (39% versus 5%; p = 0.01), occurring within 8.3 (3.53) months of surgery. On multivariable analysis, nonoperative management was associated with unplanned second surgery (odds ratio 5.5, 95% CI 1.25-24.17, p = 0.02), regardless of the type of hydrocelectomy performed. Conclusions: Nonoperative management provides effective spontaneous resolution in about 25% of infantile abdominoscrotal hydrocele. Clinicians must balance the potential benefits of such strategy against the impact of pressure induced detrimental effects on the success of future surgery when dealing with longstanding lesions. Level of evidence: III
Nitrogen fixation in the Mediterranean Sea
The Mediterranean Sea is an oligotrophic basin characterized by low nutrient levels and unusually high NO3/PO4 molar ratios in the deeper layers, that reach the maximum (N/P = 28) in the Eastern Mediterranean. An external nitrogen source needs to be claimed in order to explain the nitrogen excess. Pantoja et al. (2002) found that the 15N/14N natural abundance in particulate and in dissolved inorganic nitrogen display low values, suggesting an important role of a "light" nitrogen source. Two hypotheses can be invoked: (i) nitrogen compounds from atmospheric deposition and/or(ii)atmospheric molecular nitrogen throughout nitrogen fixation . During TRANSMED oceanographic cruise carried out in the framework of Italian project VECTOR(June 2007), N2 fixation experiments have been carried out all over the Mediterranean Sea and outside the Gibraltar Strait. Surprisingly, very low rates (< 0.10 nmol N2*l-1*d-1) have been observed in different areas of the basin, while higher values have been observed in Atlantic Ocean according with literature data. These preliminary results suggest a major role for nitrogen atmospheric deposition in shaping the NO3/PO4 anomaly of the basin. Pantoja, S., D. J. Repeta, J. P. Sachs, and D. M. Sigman (2002). Stable isotope constraints on the nitrogen cycle of the Mediterranean Sea water column, Deep Sea Res., Part I, 4, 1609- 1621
Increase of fumonisin b2 and ochratoxin a production by black Aspergillus species and oxidative stress in grape berries damaged by powdery mildew.
Powdery mildew (PM), caused by the fungus Erysiphe necator, is one of the most widespread fungal disease of grape and may cause extensive openings on the berry surface during the infection. We evaluated the effect of damage caused by PM in grape berries on the growth of and mycotoxin production by Aspergillus and on the oxidative stress in infected berries. Berries of Vitis vinifera L. cv. Negroamaro with sound skin (SS) and those naturally infected by PM were surface sterilized and inoculated with either fumonisin B2 (FB2)-producing strains of Aspergillus niger or ochratoxin A (OTA)-producing strains of Aspergillus carbonarius and incubated at 20 and 30uC. The PM berries were significantly more susceptible to both Aspergillus colonization (5 to 15 times more susceptible) and OTA and FB2 contamination (2 to 9 times more susceptible) than were SS berries. The highest toxin concentration was detected in inoculated PM berries both for OTA (9 ng/g) at 20uC and for FB2 (687 ng/g) at 30uC. In inoculated SS and PM berries, although malondialdehyde and hydrogen peroxide concentrations did not increase, the two black Aspergillus species caused a significant decrease in ascorbate content, thus inducing a pro-oxidant effect. These results indicate that grape berries affected by PM are more susceptible to black Aspergillus growth and to production and/or accumulation of FB2 and OTA. Thus, preventive control of E. necator on grape berries could reduce the mycotoxicological risk from black Aspergillus infection
The Treatment of Acute Diaphyseal Long-bones Fractures with Orthobiologics and Pharmacological Interventions for Bone Healing Enhancement: A Systematic Review of Clinical Evidence
The healing of long bones diaphyseal fractures can be often impaired and eventually end into delayed union and non-union. A number of therapeutic strategies have been proposed in combination with surgical treatment in order to enhance the healing process, such as scaffolds, growth factors, cell therapies and systemic pharmacological treatments. Our aim was to investigate the current evidence of bone healing enhancement of acute long bone diaphyseal fractures
Seasonal cycles of pH and carbonate system parameters in the southern Adriatic Sea during one year of VECTOR project
Within the VECTOR project (activity 8.1.2) the pH and other physical chemical parameters were acquired as seasonal time series from September 2007 to June 2008, at the AM1 station (in the centre of the Southern Adriatic Pit). The pH was measured by the spectrophotometric method (precision ? 0.003) and the results expressed on "total scale" at 25?C (pHT@25?C). In a few seasons also the total alkalinity (AT) was measured by potentiometric titration at 25?C (precision ? 3 Qmol/kg) and the results were checked against sea water certified as reference material (by dr. A.G. Dickson). The other derived parameters of the carbonate system (pCO2, DIC, lAr, lCa) were computed from pH, TA, salinity, temperature, SiO2, PO4 according to Lewis and Wallace 98. The pH seasonal variability was the highest in the upper layer (0-100 m), as clearly recognizable in fig 1a, b being the pH value mainly driven by biology during the productive seasons (from spring to late summer) or by mixing with deeper waters and exchange processes with atmosphere in winter. In the deeper layers (intermediate and bottom) the seasonal variability was lower but not negligible, probably driven by remineralization processes of dissolved and particulate organic matter locally produced, as suggested by Apparent Oxygen Utilization (AOU) and nitrate seasonal variabilities (fig. 1c, d, e, f). Generally, the highest differences of physical and biogeochemical properties can be observed in both the upper (0-100m ) and the intermediate (100-800 m) layers in September and June whereas during wintry season (January and February) variabilities were much lower. Through early to late summer season, the nutrients pH and dissolved inorganic carbon (TCO2) all suggest that both layers are strongly affected by biology (quite active primary production in the upper layer although in general the region has to be considered oligotrophic, and remineralisation processes in the intermediate layer). As confirmed by the good correlation with AOU and fluorescence. The vertical variabilities of such parameters are large, representing the 28 %, 0.4 %, -115 % of the total amount. Narrower changes can be observed passing from the intermediate to the bottom layer (800 - bottom) in January, February and June. A good correlation between changes of nutrients, pH, carbonate system and AOU is still observed, indicating the significant contribution of remineralisation processes to the final values. The physical and biogeochemical differences between the intermediate and the bottom layer further suggest that water masses of different origin filled these two layers. The persistence of inter layers variability through the year might suggest the absence of any abrupt change in the circulation scheme. The three forms of carbon dioxide in seawater (TCO2 aq, HCO3 -, CO3 = ) and the saturation states of calcite and aragonite were computed, from the experimental measures of pH and total alkalinity (reported in table 1) along the water column, in February June and October 2008. Values at surface show to be higher than the surface values of other oceanic regions, this is due to the higher alkalinity of the Mediterranean Sea, thus confirming peculiar characteristics of the carbonate system and the good saturation states of the Med Sea and southern Adriatic sea in particular
Decontamination of Fumonisin B1 in maize grain by Pleurotus eryngii and antioxidant enzymes
Fumonisin B1 (FB1) is among the most common mycotoxins found in maize kernels and maize products
worldwide. The microbiological process of detoxification and transformation of toxic organic pollutants is a promising
method for foodstuffs decontamination. Some basidiomycetes, such as the Pleurotus eryngii species complex,
include several important commercial edible varieties that can detoxify polycyclic organic compounds and a range
of wastes and pollutants. We investigated the potential role of P. eryngii, one of the most consumed mushrooms, in
the decontamination of FB1 in maize. In addition, selected antioxidant enzymes, (soluble peroxidase (POD), catalase
(CAT) and ascorbate peroxidase), primarily involved in control of cell hydrogen peroxide levels, and lignin
degradation, were analyzed, to evaluate their contributions to the molecular mechanisms of FB1 by P. eryngii. FB1
decontamination by P. eryngii and involvement of CAT and POD enzymes in the control of toxic decontamination
levels of H2O2 were demonstrated. A consistent reduction of FB1 was observed at different incubation times. The
average decrease levels of FB1, with respect to the control cultures, ranged from 45 to 61% (RSD < 15%). This study
is a possible eco-friendly approach to reducing this mycotoxin in the feed supply chains
Fumonisin B2 by Aspergillus niger in the grape–wine chain: an additional potential mycotoxicological risk
Fumonisins are mycotoxins with cancer-promoting activity and are associated with a number of animal and human diseases. The potential risk of contamination by fumonisin B2 (FB2), although at low levels, has been demonstrated in must and wine. Black aspergilli in general and Aspergillus niger in particular are considered to be the major responsible agents of FB2 contamination in grape and its by-products. Contamination by FB2 therefore is yet another safety concern of grape and wine producers, as ochratoxin A, produced mainly by A. carbonarius, may prove to be a major mycotoxicological problem in the grape–wine chain
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