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NATURAL INDICO FROM ISATIS TINCTORIA L. FOR THE VALORISATION OF SICILIAN CROPS
No full textIsatis tinctoria L. or woad (Brassicaceae) is an upright herbaceous biennal species up to 120 cm in
height. It is in Mediterranean counlries, a common plant cultivated through out centuries to produce
the blue dye indigo. With increasing concem for sustainability and a demand from consumers for
naturally sourced products, there is a revival of interest in naturai indigo as an agricultural crop
produci. Indigo is formed after the extraction of indigo precursors in the leaves of these plants:
mainly isatans in woad These compounds are extracted by steeping leaves in warm water. With
woad, the addition of alkali to the steep water releases free indoxyl, which forms indigo after a
vigorous aeration. Indigo is hydrophobic and insoluble in water, so that it sedimcnts readily, and the
solid indigo can be readily washed and dried. Indigo is synthesized from two precursor molecules of
indoxyl, deriving from plant secondary metabolism. Recently clarified the nature of indigo
precursors in woad (Isatis tinctoria L.), by identifying the major indoxyl glycoside as isatan A
(indoxyl-3-O-(60-O-malonyl-b-D-ribohexo-3-ulopyranoside)), and by correcting the structure of the
related isatan B (indoxyl-3-0-b-D-ribohexo-3-ulopyranoside). The seasonal variation of indoxyl
glyeosides in woad leaves was investigated and the influence of various post-harvest treatments was
studied and Isatans A and B disappeared completely when the leaf material was submitted to a
conventional drying process. In contrast, the indican coment in leaves increased significantly, and
the extent of this increase was temperature-dependent. These precursor can be identified and
quantified by HPLC method since their quantity in dependent on the species and the harvest period.
The modem extraction method of indigo from woad uses the water solubility of the indigo
precursors in steeping the leaves in hot water. The precursors are broken down to indoxyl and sugar
moieties by endogenous enzymes in plant (glycosidases), but in the extraction method this is done
by alkali with aeration. The purity of plant-derived indigo even with the modem extraction method
is somewhat low when compared to the synthelic indigo. Naturai indigo contains besides indigo,
impurities such as indirubin, indigo-brown, indigo gluten and minerai matter. Several authors
indicate that indigo can be extracted from woad with a purity of 90% if three conditions are met: the
leaves contain a sufficiently high yield of indigo precursors; the leaves are rinsed free of soil; and
the indigo is sedimented in an acid medium
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Shrimp dating of zircons in eclogite from the Hercynian basement from north eastern Sardinia (Italy)
No full textSHRIMP (Sensitive High-Resolution Ion Microprobe) U–Pb ages of zircons from a single sample of mafic eclogite (Punta de li Tulchi, Sardinia, Italy) are reported. The study under cathodoluminescence (CL) reveals two groups of metamorphic zircons and the SHRIMP analyses allow recognition of three stages: 1) 453 +/- 14 Ma; 2) 400 +/- 10 Ma; and 3) 327 +/- 7 Ma. The age of 453 +/- 14 Ma could be that of the magmatic protolith and an age of 327 +/- 7 Ma can reasonably be attributed to the main Variscan collisional event in Sardinia, which produced Barrovian-type metamorphism, and retrogression of eclogite under amphibolite-facies metamorphism. The intermediate age 400 +/- 10 Ma is difficult to interpret and it could represent either the age of the eclogite facies metamorphism or it is a result of Pb-loss during the main Variscan event at 327 +/- 7 Ma
New application of agro-industrial waste to prevent melanosis of Mediterranean pink shrimp.
No full textMulti-stage metamorphic re-equilibration in eclogitic rocks from the Hercynian basement of NE Sardinia, Italy
No full textEclogitic rocks are hosted within gneisses and migmatites of the Hercynian basement of NE Sardinia. They are characterized by two compositional layers: garnet-pyroxene rich-layers and amphibole-plagioclase layers. The former contain structural, mineralogical and compositional relics of eclogite facies re-equilibration. Four stages of evolution have been identified: an eclogite stage, a granulite stage and a retrograde amphibolite to greenschist stage. A possible pre(?)-eclogite stage is documented by inclusions of euhedral tschermakitic amphibole + zoisite within the core of garnet. This early stage was followed by an increase in pressure under which the eclogite climax developed (T up to 700 °C, P = 13-15 kbar), as documented by omphacite inclusions towards the rim of garnet. Characteristic mineral reactions after the eclogitic stage are: omphacite → diopside + plagioclase (symplectite) and garnet → orthopyroxene + plagioclase. These reactions testify the presence of a granulite stage during which the peak of metamorphism was reached (T up to 870 °C, P ≈10 kbar). The orthopyroxene → cummingtonite + quartz and garnet + diopside → hornblende + plagioclase (kelyphite) transformations indicate extensive amphibolite retrogression (T = 550-650 °C, P = 3-7 kbar). Finally, actinolite and chlorite developed (greenschist stage) at falling temperature and pressure (T = 300-400 °C, P < 2-3 kbar)
Boninite-derived amphibolites from the Lanterman-Mariner suture (northern Victoria Land, Antarctica): New geochemical and petrological data
No full textIn northern Victoria Land (Antarctica) the Lanterman-Mariner suture separates the inboard Wilson Terrane from the outboard Bowers and Robertson Bay terranes. This boundary is characterized by the presence of discontinuous bodies of mafic to ultramafic rocks with a metamorphic grade ranging from medium-P amphibolite facies (Mountaineer Range) to ultrahigh-P eclogite facies (Lanterman Range). The Dessent Ridge is a narrow tectonic slice occurring along the Lanterman-Mariner suture in the Mountaineer Range. The slice mainly consists of amphibolites and amphibole-rich schists with very peculiar mineral assemblages comprising talc + clinoamphibole + orthoamphibole +/- staurolite +/- garnet. Talc shows very unusual compositions with significant Al and Na contents linked to the Si-1 square-1Al+1Na+1 and Si-1Mg-1Al+2 substitutions (i.e. "tschermak talc"). Bulk-rock major, trace-element and REE compositions range from MORB/arc tholeiite to boninite. Along the Lanterman-Mariner suture the presence of metamorphic rocks whose protoliths have a boninitic affinity is here reported for the first time. They attest to the past existence of a subduction zone with an arc-backarc system between the Wilson and the Bowers terranes. Mineral assemblages and the mineral chemistry allow us to document a retrograde P-T-path from a regional medium-P amphibolite (T approximate to 690 degrees C; P approximate to 0.9 GPa) to greenschist facies, with a typical cooling-unloading path. Amphibolite-facies metamorphism was followed by structural reworking and partial recrystallization under strike-slip shear deformation. The rocks most affected by shearing document that this deformation developed under the transition amphibolite-greenschist facies, although local higher temperature conditions can be ascribed to shear heating. Comparison with other mafic-ultramafic rocks from the Lanterman-Mariner suture suggests that, from the regional amphibolite-facies metamorphism onwards, the area extending from the Lanterman Range to the Mountaineer Range, including the Dessent Ridge, underwent a nearly synchronous tectono-metamorphic evolution. The Lanterman-Mariner suture resulted from the accretion of an arc/backarc system to the palaeo-Pacific continental margin of Gondwana during the Ross Orogen (Cambro-Ordovician), a typical subduction-accretion orogen. (C) 2012 Elsevier B.V. All rights reserved
DETERMINATION AND CHARACTERIZATION OF A LIPOXYGENASE FROM OPUNTIA FICUS INDICA (L.MILLER).
No full textRegional metamorphism and P-T evolution of the Ross Orogen in northern Victoria Land (Antarctica): a review
No full textThe main focus of this paper is on the petrological evolution of medium- to high-grade metamorphic units in the Wilson Terrane, the westernmost lithotectonic unit of the Ross Orogen in northern Victoria Land. The petrological data set is reviewed for all areas where P-T-t paths have been reconstructed and geochronological data are sufficiently complete to provide an overview of the regional metamorphic evolution of a ca. 600 km long segment of the Ross Orogen, from its termination along the Pacific coast to the Eisenhower Range near the Ross Sea coast. Petrological evidence reveals that different lithological units of the Wilson Terrane equate with distinct lithotectonic metamorphic complexes with partly independent P-T-t histories. In spite of the wide range of estimated peak metamorphic conditions, and variability in both shape of the P-T path (clockwise or counter-clockwise) and type of retrograde evolution (isobaric cooling or cooling/unloading), the reviewed P-T-t trajectories consistently support a setting of evolving subduction and accretion in the context of a Palaeozoic cordilleran-type active margin
Ultra high pressure metamorphism in felsic rocks: the garnet – phengite gneisses and quartzites from Lanterman Range (Antarctica)
No full textMesostructural and microstructural relations between eclogitic boudins and country gneisses in the Ross Orogen of the Lanterman Range (Northern Victoria Land, Antarctica) are in some areas characterized by interlayering with sharp contacts on a cm scale, which indicate that the two rock-types underwent a common metamorphic evolution. Contrary to many other UHP felsic rocks that only preserve a poor record of the HP stage, the studied rocks have recorded a metamorphic history ranging from initial prograde amphibolite facies through the eclogite facies to the retrogressive amphibolite facies. The prograde amphibolite stage is documented by garnet relics preserving prograde zoning and bearing biotite, plagioclase, muscovite, phengite and rutile inclusions. The eclogite stage is characterized by the coexistence of phengite with pyrope-grossularite rich garnet, the latter containing phengite and paragonite inclusions, and by radial fractures within garnet around quartz pseudomorphs after coesite. Symplectites have formed during the amphibolite-facies retrogression. They consist mainly of biotite + plagioclase around phengite and garnet; muscovite, biotite and plagioclase grew along the main foliation. The reconstructed metamorphic evolution, involves a steep prograde and retrograde PT path as well as a HP-T peak. Along with the geochronological evidence of fast exhumation, this supports a model of arc-continent collision, with the HP rocks belonging to the over-riding plate. Their exhumation is mainly controlled by extension related to renewed "rollback" of subduction in front of the orogenic zone
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