670 research outputs found
Mammalian hippocampal neuronal plasticity under normal and pathological conditions
No full textNeuroplasticity is a term that includes all the functional and structural changes within a neural circuit in response to external or internal events, changes at synaptic level, in the morphology, or in the number of cells. These changes are related with functional modifications and have great relevance under physiological conditions and in neuropathology.
The malleability of the nervous system has a central role in shaping the brain during prenatal and early postnatal development, in the childhood, but also in the adulthood, supporting vital functions, such as learning and memory. Therefore, the first part of this PhD thesis is focused on study about the mechanism of physiological plasticity in the hippocampus in relation with network activation induced by common every-day experiences, such as physical activity. Hippocampus, indeed, attracts great attention in the neuroscience research field because it takes part to certain types of learning and memory but also because of its extraordinary degree of neuronal plasticity. In this structure, much of the attention is mainly focused on neuronal plasticity phenomena, such as synaptic Long Term Potentiation (LTP) and adult neurogenesis: this last phenomenon represents a fascinating example of plasticity occurring in a specific hippocampal area called Dentate Gyrus (DG). Here, new granule cells are daily generated and incorporated in the existing network. In the hippocampus, stem/progenitor cell proliferation and newly-generated granule cell integration are affected by numerous stimulus both physiological and pathological. In keeping with this statement, physical exercise represents a pro-neurogenic activity. Our previous findings highlighted that a brief physical activity, and in particular voluntary running, produces short-term effects in very immature newborn granule cells of adult DG. Here, the attention is shifted in the research for possible long-lasting effects of voluntary running on newly-generated granule cells, evaluating morphological and possible functional implications related with this activity, with the purpose of removing part of the shadows upon the possible mechanism of cognitive enhancement widely reported in association with physical exercise.
Additionally, since abnormal plastic adaptation underlies many neural diseases, the second part of this thesis has considered two pathologies, depression and epilepsy, in order to uncover and highlight possible treatments able to influence, or prevent, the aberrant plastic support to these neuropathologies. Concerning depression, the focus was placed on the study of Fibroblast Growth Factor Receptor 1 – 5-hydroxytryptamine 1A (FGFR1-5HT1A) heteroreceptor complex role in depression, which is a receptor-receptor (R-R) interaction of extreme interest since it represents the meeting point between two theories of depression, the serotoninergic and the neurotrophic factor hypotheses. The FGFR1-5HT1A heteroreceptor complex is reported to exist in hippocampus. In addition, combined agonist treatment influences cellular throphism and morphology, suggesting that activation of FGFR1-5HT1A heteroreceptor complex might be related with antidepressant effect of serotonin in the brain and, combined activation of both receptors might result in more rapid and stronger antidepressant action than that found with Selective Serotonin Reuptake Inhibitors (SSRIs). Indeed, an important clinical pursuit in the depression field is the research for fast-acting treatments or molecules able to speed up the effects of the canonical anti-depressive drugs, since commonly available treatments exert their therapeutic action after a delay that last from weeks to months. Thus, the attention has been focused on a first evaluation about the therapeutic potential of combined FGFR1 and 5HT1A agonist treatment, which has been firstly tested on Sprague Dawley (SD) rats, using electrophysiological, molecular and behavioural approaches. Afterward, to evaluate if disturbances of the FGFR1-5HT1A heteroreceptor complex might exist in depression and if the combined treatment with the agonists of the FRGR1 and 5-HT1A could exert antidepressant effects, the attention was moved on Flinders Sensitive Line Rats (FSL), a well-known model of depression. Actually, the potential existence of disturbances in depression at FGFR1-5HT1A heteroreceptor complex level could represent an exciting finding since it might confirm these complexes as valid targets for future therapeutic treatments with possible fast-acting properties. The other pathology investigated in the second part of this PhD thesis is the mesial temporal lobe epilepsy (MTLE), the most common form of localization-related epilepsy, which is characterised by progressive plastic rearrangements that lead to the chronicization of the disease and the aberrant remodelling of the hippocampal network. Treatment able to counteract the chronicization of epilepsy represents an unmet clinical need. Previous findings from our laboratory of physiology suggested a potential and promising role of Vitamin E (as -tocopherol) as antiepileptogenic treatment, which might act through different mechanisms than anti-oxidant one. To validate this assumption, using the kainate rat model of epilepsy, the excitability of hippocampus circuitry, the neuroinflammation markers, neuron cell death and microRNA (miRNAs) expression, have been investigated in adult rat after 15-days of -tocopherol treatment.
Overall, essential cognitive process but also several neuropathologies have a common underlying feature called brain plasticity, which plays a double but opposite role in these different conditions, thus being of huge interest for neuroscience and all human life. Accordingly, managing to manipulate brain plasticity is gaining great attraction for its potential in health and disease. On one hand, it might improve essential features as learning, memory and cognition: indeed, a brief physical activity creates short-term and long-lasting modifications in hippocampus, which could influence future network activity and lead to cognitive enhancement. On the other hand, the research for treatments potentially able to counteract aberrant plastic changes in disease, as those observed in depression or epilepsy, might represent a promising approach aimed to correct the mechanisms behind the pathology and not the symptoms themselves
Raphitoma petanii Prkic, Giannuzzi-Savelli & Pusateri 2020, n. sp.
No full textRaphitoma petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. (Figs 3 A-G; 4 A-H; 6 A-C; 7 A, B) urn:lsid:zoobank.org:act: 779382FF-84AC-451D-932D-C27E6BAE6AD3 Raphitoma sp. B – Russini et al. 2020: 301. TYPE MATERIAL. — Holotype. Croatia • lv; MNHN-IM-2000-34887 (height 10.65 mm, width 3.93 mm); Stari Trogir Bay; 43°29’21”N, 16°02’37”E; 1-4 m depth. Paratypes. Croatia • 1 lv; MNHN-IM-2000-34888; same locality data as holotype • 1 lv; MCZR-M-TYPE-00118; same locality data as holotype • 1 lv; HPM 11500; same locality data as holotype • 1 lv; MZB 60233; same locality data as holotype • 12 lv; coll. PRK; same locality data as holotype • 2 lv; coll. RGS- 120245, coll. RGS- 120246; same locality data as holotype • 1 lv; coll. PUS-2798; same locality data as holotype • 1 lv; coll. PET; same locality data as holotype • 6 lv; BAU-2269.1-3, BAU-2273.1, BAU-2273.3, BAU-2273.4; Sukošan; 44°01’30”N, 15°20’50”E; 2-6 m depth. TYPE LOCALITY. — Croatia, Stari Trogir Bay (Sevid); 43°29’21”N, 16°02’37”E; 1-4 m depth. OTHER MATERIAL EXAMINED. — Croatia • 1 lv; coll. PET; Vrsi, Jase- novo • 1 lv; coll. PET; Zaton, Bilotinjak • 6 lv; coll. PET; Sukošan, Mala Makarska • 1 lv; coll. PET; Sukošan, Tustica • 1 lv; coll. PET; Turanj • 9 lv; coll. PRK; Biograd, Bošana • 58 lv; coll. PET; Biograd, Bošana • 1 lv; coll. PET; Pakoštane • 3 lv, 3 sh; coll. PRK; Murter Island, Kosirina Bay • 1 lv; coll. PET; Murter Island, Kosirina Bay • 7 lv, 2 sh; coll. PRK; Sevid, Stari Trogir Bay • 24 lv; coll. PET; Se- vid, Stari Trogir Bay • 5 lv; coll. RGS; Sevid, Stari Trogir Bay • 5 lv; coll. STA; Brač Island, Milna • 9 lv; coll. STA; Brač Island, Maslinova Bay • 1 lv; coll. PRK; Duće Vavlje • 3 sh; coll. PRK; Mljet Island. DISTRIBUTION. — This species is so far known only from Croatia, based on the material examined, with samples collected in 0-19 m depth, but we do not exclude the possibility that it occurs also in some other Mediterranean areas. ETYMOLOGY. — After Alen Petani, for his great contribution to the study of the Croatian raphitomids and to the present paper. HABITAT. — This species has been collected on rocky bottoms with plenty of small and medium-sized stones, on the underside of which the specimens are found at daytime. This is a shallow-water species, more than 150 live specimens having been found at 0.5-4 m depth, and only a few on slightly deeper bottoms (max 19 m, at Brač Island: R. Stanić, pers. comm.). R. petanii Prkić, Giannuzzi- Savelli & Pusateri n. sp. often lives in sympatry/syntopy with other raphitomids (Cyrillia linearis, Leufroyia concinna (Scacchi, 1836), L. leufroyi (Michaud, 1828), Raphitoma contigua, R. cordieri, R. densa, R. echinata AA. - morphotype 2 [see below], R. laviae, R. stanici Prkić, Giannuzzi-Savelli & Pusateri n. sp., etc.), sometimes with specimens of 5-6 different species occurring under the same stone. DESCRIPTION [in square brackets the data of the holotype] Shell Solid, fusiform-acute, of medium size for the genus. Height: 8.2-12.4 mm [10.65]; width: 3.06-4.94 mm [3.93]; h/d: 2.38-2.84 [2.71]. Protoconch Multispiral, of 2.6-3.25 [2.9] convex whorls. Height: 546 µm, maximum diameter: 447 µm (in specimen with PW = 3.1, Fig. 6 A-C). Protoconch I of 1 whorl, 196 µm in diameter, covered by dense cancellate sculpture; protoconch II with axial threads below the suture and less dense and diagonally cancellate sculpture on the rest of whorl. A strong keel at the end of last whorl covered with microgranules, denser above the keel. Protoconch-teleoconch boundary of flexuose, opisthocline growth lines. Colour brownish with white nucleus. Teleoconch Of 6.1-7.25 [7] slightly convex, not stepped whorls, suture incised, sculpture prominent, whole surface covered with dense microgranules. Axial sculpture of 18-27 [24] equidistant, narrow, orthocline or slightly opisthocline ribs, narrower than interspaces, broader than spiral cords. Spiral sculpture of 20-26 [23] spiral cords on the last whorl, of which 6-8 [7] primary cords above the aperture, and two [2] secondary cordlets on the subsutural ramp. Siphonal fasciole with 9-12 [10] strong nodulose cords. Cancellation usually subquadrate, sometimes slightly rectangular, with not very elongate tubercles at intersections; tubercles on first 3 adapical primary cords more or less spinulose, often also on secondary cordlets. Subsutural ramp narrow, inclined. Columella simple, straight and inclined to the right anteriorly, gently angled posteriorly.Siphonal canal of medium length, widely open at the end; posterior canal broad. Outer lip thick, with 9-14 [11] strong inner plicate denticles. Colour Brownish or chestnut brown background, often very dark, sometimes with brown-yellowish or brown-greyish hue, interspaces always darker. White, whitish or ash grey blotches and spots of variable size, occasionally absent or very small, or covering most of surface. Soft parts Foot long and broad, deeply bilobed anteriorly and with recurved anterolateral corners, narrowly tapering posteriorly. Head small with a pair of long cylindrical tentacles, black eyes on bulges about halfway along their length, the distal part slightly longer and much narrower than the basal. Proboscis rather long and much narrower at the base than at the tip. Colour translucent white or yellowish-white on background, with minute white speckles covering the whole body, including entire length of tentacles, scattered or absent on the sole. Black to dark-grey pigments on head around the base of tentacles and extending on right side down to about halfway to edge of foot. Siphon tip with dense white speckles and a translucent white or yellowish ring, rest of siphon dark grey or grey-brownish with few and scattered white specks. Proboscis pure white and without specks. Diagnostic nucleotides 37, 70, 112, 250, 533, 539 (COI), and 297 (ITS2). REMARKS The number of teleoconch whorls significantly varies in specimens of the same size, while specimens very different in size may have the same number of TW: for example, two specimens 10.28 mm and 8.35 mm long, respectively, both have the same number of whorls (6.25). Sometimes only one cordlet (adapical) may be present in the frontal view, but also in such cases the other one always gradually appears on the dorsal side of the last whorl, so at dorsal side both secondary cordlets are always present. These two secondary cordlets are often quite strong and with spinulose nodules, so they often look almost as primary cords. This species can be confused only with Raphitoma densa (Monterosato, 1884) with which is often found living in sympatry. In Croatia, where R. petanii Prkić, Giannuzzi- Savelli & Pusateri n. sp. is c. 5 times more frequent than R. densa, the two species live in the same bathymetrical range and habitat, and no living or dead specimen has ever been found deeper than 19 m. They share the presence of microgranules over the whole teleoconch, a similar protoconch, same maximum size of the shells, and same colour pattern of the soft parts. In our molecular phylogenetic analyses, R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. and R. densa were sister species, reciprocally monophyletic and their genetic divergence (K2p) was 5-7%, indisputably above the species level threshold. R. densa is rather variable across its range in the Mediterranean (Giannuzzi-Savelli et al. 2018). However, Croatian specimens of R. densa have quite constant morphological characters which, in most cases (and with very few exceptions), allow to distinguish them relatively easily from shells of R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. Therefore, we provide here diagnostic features between the two species as observed in the Croatian material. Protoconch The number of whorls varies similarly in both species, with R. densa showing only slightly fewer whorls (2.5-3.0, mean 2.79) than R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp., (2.6-3.25, mean 2.98). Also the exposed height of the protoconch seems to be slightly different, in a specimen of R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. (Fig. 6 A- C) with 3.1 protoconch whorls the height is 546 µm, while in a specimen of R. densa (Fig. 6D, E) with 3.0 whorls the height is 508 µm. Axial ribs Axial ribs are much stronger and broader in R. densa than in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp., and as a consequence also the tubercles are much more elongated in R. densa. Their number is also frequently (though not always) higher in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. (18-27, mean 22.55), than in R. densa (16- 19, mean 17.46). Spiral cords The spiral sculpture above the aperture consists in both species of primary cords and two secondary cordlets on the shoulder between a narrow subsutural ramp and the first primary cord. In R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. these two secondary cordlets are often quite strong and with spinulose nodules, so they often look al- most as primary cords, while in R. densa they are much weaker. In R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. the spiral cords are only slightly weaker than the ribs, while in R. densa the ribs are much stronger than the cords. The spiral cords on the last whorl are often less numerous in R. densa (19-22, mean 20.64) than in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. (20-26, mean 23.5); above the aperture there are 5-6 (mean 5.85) primary cords in R. densa and 6-8 (mean 6.96) in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. Apertural denticles There are often slightly fewer denticles in R. densa (8-10, mean 9.5) than in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. (9-14, mean 11.32). Subsutural ramp In both species the subsutural ramp is narrow, but in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. the first secondary cordlet is very close to the suture and the ramp is quite inclined. In R. densa the first secondary cordlet is not so close to the suture and the ramp is much less inclined, resulting in more stepped whorls. White comma-shaped marks, which are very often present on the ramp of R. densa, are rarely observed in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. Tubercles They are more elongated and bluntly elevated in R. densa (only on the first 3 primary cords they can be moderately spinulose). In R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. the tubercles on the first 3 primary cords and two secondary cordlets are more or less spinulose, often very spinulose. Colour The variation in colour of the teleoconch mostly overlaps in the two species, but only R. densa always have many large white blotches, while in R. petanii Prkić, Giannuzzi- Savelli & Pusateri n. sp. these blotches can be present, but also completely absent (in the latter cases R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. is very easily diagnosed). Slenderness (h/d) The shells of R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. are generally more slender (h/d = 2.38-2.84, mean 2.6) than those of R. densa (h/d = 2.24-2.46, mean 2.37). Other differences Young and subadult shells are broader in R. densa, while at these growth stages R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. already has a quite slender shell. General aspect of the outline of the shells is different, being more fusiform in R. petanii Prkić, Giannuzzi-Savelli & Pusateri n. sp. because the whorls are not stepped. R. densa has a somewhat more robust aspect of the shell and more robust and less dense teleoconch sculpture.Published as part of Prkić, Jakov, Giannuzzi-Savelli, Riccardo, Pusateri, Francesco, Russini, Valeria, Fassio, Giulia & Oliverio, Marco, 2020, Three new species of Raphitoma Bellardi, 1847 (Mollusca, Gastropoda, Raphitomidae) from Croatian waters (NE Adriatic Sea), pp. 215-237 in Zoosystema 42 (16) on pages 219-225, DOI: 10.5252/zoosystema2020v42a16, http://zenodo.org/record/387230
Comparing two approaches to the K-theory classification of D-branes
No full textWe consider the two main classification methods of D-brane charges via K-theory, in type II superstring theory with vanishing B-field: the Gysin map approach and the one based on the Atiyah-Hirzebruch spectral sequence. Then, we find out an explicit link between these two approaches: the Gysin map provides a representative element of the equivalence class obtained via the spectral sequence. We also briefly discuss the case of rational coefficients, characterized by a complete equivalence between the two classification methods
Рерихи : мифы и факты : сборник статей, sous la direction de A. I. Andreev, D. Savelli
No full textNiqueux Michel. Рерихи : мифы и факты : сборник статей, sous la direction de A. I. Andreev, D. Savelli. In: Revue des études slaves, tome 82, fascicule 4, 2011. La syntaxe des numéraux dans les langues slaves, sous la direction de Stéphane Viellard. pp. 759-761
Sperandio Savelli: Agostiono Barbarigo
No full textObjavljujući nepoznati primjerak rijetke medalje S. Savellija iz zbirke Arheološkog muzeja u Zagrebu, autor je u svojoj studiji spomenuo i nekoliko drugih medalja od istog autora, sačuvanih u hrvatskim muzejima i galerijama. Uz biografiju i i nterpretaciju stilskog izraza S. Savellija, autor donost i iscrpan katalog svih njegovih do danas sačuvanih i poznatih medaljerskih radova.Indem er ein unbekanntes Exempler einer seltenen Medaille von S. Savelli aus dem Archaologischen M»seum in Zagreb publiziert, zahlt der Verfasser in seiner Studie noch einige Medaillen desselben Autors in kroatischen Museen und Galerien auf. Neben der Biographie und Interpretation der stilistischen Ausdrucksweise von S. Savelli bringt der Autor auch einen ausfuhrlichen Katalog aller seiner bekannten und bis heute erhaltenen Medailleurarbeiten.In this paper the author discusses one of the 200-odd medals of the Italian Renaissance kept in the Department of Coins and Medals of the Archeological Museum in Zagreb. It is the rare medal of the Venetian dodge Agostino Barbarigo (born 1419, dodge 1486, abdicated 1501), by Sperandio Savelli (born c. 1425, died 1504) with the bust of Barbarigo three quarters to the right , with a long beard, wearing the ducal cap and mantle, on the obverse. The legend is: (rose) AVGVSTINVS BARBADICVS VENETORVM DVX On the reverse one can see the doge in cap and robes, kneeling right and holding a banner with the lion of St. Mark; before him is the Lion of St. Mark, standing, left, nimbate, holding a book with his right forepaw. Both are on a rocky ground. Both the obverse and the reverse show a plain border. The legend on the reverse is: (leaf)OPVS(leaf)/ SPERA/NDEI , in exergue, (Armand I, 75, 46; Hill. p. 103, 401, P1.75; Hall 66). This medal was cast during Sperandio s year spent in Mantua (1495 — 1496) to commemorate the victory over the French and their king Charles VIII at Fornovo on 6th June 1495. Except for a few scratches and a hole, it is well preserved. It entered the Zagreb Collection in 1894 as a gift of Dr. Gjuro Catti of Rijeka. There are three more medals by Sperandio Savelli in museums of Croatia: the portrait of Andrea Barbazzo (Armand I, 64, 4; Hill 384) at the Town Museum in Split , the medal od Giovanni Bentivoglio II (Armand I , 65, 7; Hill 355) at the Museum of Applied Arts in Zagreb and a battered specimen of the Federigo Montefeltro medal (Armand I , 71, 29; Hill 389) at the Museum of the Požega Valley at Slavonska Požega
Classifying A-field and B-field configurations in the presence of D-branes
No full textWe “solve” the Freed-Witten anomaly equation, i.e., we find a geometrical classification of the B-field and A-field configurations in the presence of D-branes that are anomaly-free. The mathematical setting being provided by the geometry of gerbes, we find that the allowed configurations are jointly described by a coset of a certain hypercohomology group. We then describe in detail various cases that arise according to such classification. As is well-known, only under suitable hypotheses the A-field turns out to be a connection on a canonical gauge bundle. However, even in these cases, there is a residual freedom in the choice of the bundle, naturally arising from the hypercohomological description. For a B-field which is flat on a D-brane, fractional or irrational charges of subbranes naturally appear; for a suitable gauge choice, they can be seen as arising from “gauge bundles with not integral Chern class”: we give a precise geometric interpretation of these objects
I terrazzi vallivi del 1° ordine nei bacini dei fiumi Metauro e Foglia (Appennino marchigiano)
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