470 research outputs found
Madagascar avant Madagascar : l’île Ménouthias des anciens et les premières représentations de l’île de Saint Laurent
Le présent travail essaie d’éclairer des questions concernant l’île Madagascar. Tout d’abord, s’agit-il vraiment de l’île Ménouthias mentionnée à plusieurs reprises par les géographes grecs ? Était-elle connue dans l’Antiquité gréco-romaine ? Deuxièmement, ce travail suit l’évolution des représentations cartographiques de l’île, avant et après sa découverte (1500).This study tries to clarify some questions concerning Madagascar. Firstly, is it really the Ménouthias island mentioned on several occasions by the Greek geographers? Was it known in Graeco-Roman Antiquity? Secondly, it follows the evolution of the cartographical representations of the island, before and after its discovery (1500)
Degradation of Aflatoxin B1 by a Sustainable Enzymatic Extract from Spent Mushroom Substrate of Pleurotus eryngii
Ligninolytic enzymes from white-rot fungi, such as laccase (Lac) and Mn-peroxidase (MnP), are able to degrade aflatoxin B1 (AFB1), the most harmful among the known mycotoxins. The high cost of purification of these enzymes has limited their implementation into practical technologies. Every year, tons of spent mushroom substrate (SMS) are produced as a by-product of edible mushroom cultivation, such as Pleurotus spp., and disposed at a cost for farmers. SMS may still bea source of ligninolytic enzymes useful for AFB1 degradation. The in vitro AFB1-degradative activity of an SMS crude extract (SMSE) was investigated. Results show that: (1) in SMSE, high Lac activity (4 U g−1 dry matter) and low MnP activity (0.4 U g−1 dry matter) were present; (2) after 1 d of incubation at 25 °C, the SMSE was able to degrade more than 50% of AFB1, whereas after 3 and 7 d of incubation, the percentage of degradation reached the values of 75% and 90%, respectively; (3) with increasing pH values, the degradation percentage increased, reaching 90% after 3 d at pH 8. Based on these results, SMS proved to be a suitable source of AFB1 degrading enzymes and the use of SMSE to detoxify AFB1 contaminated commodities appears conceivable
Performance evolution and tensile behaviour of long-term exposed UHPC under sustained load, aggressive environments and autogenous healing
An extended experimental campaign was conducted to analyse the evolution of UHPC tensile performance over time as affected by sustained flexural load and aggressive environments both interacting with its autogenous self-healing capacity. A new methodology including both destructive and non-destructive tests was proposed. Three different mix designs were tested, with steel fibres, crystalline admixture, and various nanomaterials. Specifically, the first batch included alumina nano-fibres, while the second one cellulose nanocrystals. The last one was used as a reference and did not include nanomaterials. Thin beam specimens (500x100x30 mm) were pre-cracked and exposed to three different environments, under four-point bending sustained load. The specimens were cured for 1, 2, 3, 6, 9, and 12 months respectively, being exposed to a chloride solution, geothermal water, and tap water as a reference. After the aforesaid scheduled exposure times, two nominally identical specimens were tested for each condition, the first in four-point bending and the second in direct tension. To compare the results, a simplified five-point inverse analysis was adapted for beams with different slenderness, providing a quadrilinear constitutive law derived from the structural flexural behaviour of four-point bending tests. Test results allowed to highlight the effects of each parameter – type of material and exposure – on the self-healing effectiveness and the tensile response, also defining their evolution over time. The self-healing process resulted in an almost complete recovery after the first two or three months, and the materials were able to maintain a constant performance over longer periods, regardless of the conditions they were exposed to
Investigating alkyl nitrates as nitric oxide releasing precursors of multitarget acetylcholinesterase-monoamine oxidase B inhibitors
Herein we envisaged the possibility of exploiting alkyl nitrates as precursors of alcohol-bearing dual inhibitors targeting acetylcholinesterase (AChE) and monoamine oxidase B (MAO B), key enzymes in neurodegenerative syndromes such as Alzheimer's disease (AD), through biotransformation unmasking an alcoholic function upon nitric oxide (NO) release. The cooperation to neuroprotection of low fluxes of NO and target enzymes’ inhibition by the alcohol metabolites might return a multitargeting effect. The in vitro screening towards ChEs and MAOs of a collection of 21 primary alcohols disclosed a subset of dual inhibitors, among which three diverse chemotypes were selected to study the corresponding nitrates. Nitrate 14 proved to be a brain permeant, potent AChE-MAO B inhibitor by itself. Moreover, it protected human SH-SY5Y lines against rotenone and hydrogen peroxide with a poor inherent cytotoxicity and showed a slow conversion profile to its alcohol metabolite 9d that still behaved as bimodal and neuroprotective molecule
Sodium piperidine-1-carbodithioÂate dihydrate
The asymmetric unit of the title compound, Na+·C6H10NS2
−·2H2O, is composed of a sodium cation, a piperidineÂdithioÂcarbamate anion which exhibits positional disorder, and two lattice water molÂecules. The atoms of the piperidine ring are divided over two sites with occupancy factors of 0.554 (6) and 0.446 (6). In the crystal, the sodium cation (coordination number of 6) and the piperidineÂdithioÂcarbamate anion are linked, forming an infinite two-dimensional network extending parallel to (001). O—H⋯S hydrogen bonds, involving the lattice water molÂecules, also aid in stabilizing the crystal sructure
Cardiovascular dysfunction and vitamin D status in childhood acute lymphoblastic leukemia survivors
Vitamin D (25-OHD) has a role in bone health after treatment for cancer. 25-OHD deficiency has been associated with risk factors for cardiovascular disease, but no data focusing on this topic in childhood cancer survivors have been published. We investigated the 25-OHD status in children treated for acute lymphoblastic leukemia (ALL), and evaluated its influence on vascular function
Is secondary hyperparathyroidism-related myelofibrosis a negative prognostic factor for kidney transplant outcome?
Secondary hyperparathyroidism (HP) presenting with hypocalcemia and subsequent increased parathormone (PTH), is mainly identified in patients with chronic renal failure, which has been associated with variable degrees of bone marrow fibrosis. For suitable patients with end-stage renal disease (ESRD), kidney transplantation is recognized as the therapy of choice, being superior to dialysis in terms of quality of life and long-term mortality risk; in this regard interesting data show that increased time on dialysis prior to kidney transplantation is associated with decreased graft and patient survival. In our opinion an important and until now underestimated determinant of graft survival is the proper activity of bone marrow because of the emerging role of hematopoietic stem cells (HSC) in repair of ischemia/reperfusion (IR) damage. We postulate that in ESRD patients, who usually undergo long dialytic treatment, a myelofibrosis caused by an overt secondary HP could drastically decrease the HSC potential for IR damage repair after kidney transplant; this could irremediably lead to a delay in graft function with all related complicances. If the curative role of bone marrow-derived stem cells was confirmed by more data obtained in experimental animal models, it could be possible to try a cellular-based therapeutic approach in the management of ESRD patients which are in waiting list for a kidney transplant
THE MEDITERRANEAN DIET: A HISTORY OF HEALTH
The Mediterranean tradition offers a cousine rich in colors, aromas and memories, which support the taste and the spirit of those who live in harmony with nature. Everyone is talking about the Mediterranean diet, but few are those who do it properly, thus generating a lot of confusion in the reader. And so for some it coincides with the pizza, others identified it with the noodles with meat sauce, in a mixture of pseudo historical traditions and folklore that do not help to solve the question that is at the basis of any diet: combine and balance the food so as to satisfy the qualitative and quantitative needs of an individual and in a sense, preserves his health through the use of substances that help the body to perform normal vital functions. The purpose of our work is to demonstrate that the combination of taste and health is a goal that can be absolutely carried out by everybody, despite those who believe that only a generous caloric intake can guarantee the goodness of a dish and the satisfaction of the consumers. That should not be an absolute novelty, since the sound traditions of the Mediterranean cuisine we have used for some time in a wide variety of tasty gastronomic choices, from inviting colors and strong scents and absolutely in line with health
Organismi geneticamente modificati: definizioni e finalità .
Article 2 of the European Directive 2011/18/EC defines a genetically modified organism (GMO) a san organism in which the genetic material has been altered in a way that does not occuirr naturally by inserting DNA fragments from one organism's gene into the chromosomes of another, changing its genetic expression. In the field of animal and plants biotechnology there are different application areas of genetic engineering such as improving the quantity and quality of argicultural production, pharmaceutical production in more sustainable ways or applications in environmental field
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