Search results for "ASTER"
showing 10 items of 2223 documents
Reversal of asymmetric induction in stereoselective strecker synthesis on galactosyl amine as the chiral matrix
1988
Abstract The reversal of the direction of asymmetric induction in Lewis acid catalyzed Strecker synthesis using the 2,3,4,6-tetra-O-pivaloyl-β-D-galactopyranosyl amine 1 is described. In isopropanol or tetrahydrofuran 1 had given ( R )-diastereomers of the corresponding α-amino nitriles preferably. However, in chloroform in the presence of heterogeneous zinc chloride the same auxiliary alternatively leads to an excess of the ( S )-diastereomers.
Perceived classroom goal structures as predictors of students’ personal goals
2020
This study focused on the question of how to enhance a mastery-goal orientation in the classroom. We started from the perspective of the achievement goal theory, which assumes that the goals that students have (personal goals) relate to the goals that are set in the classroom (classroom goal structures). In classrooms where teachers focus on learning and effort -instead of normative standards and social comparison- mastery goals are enhanced. This type of classroom can be endorsed by focusing on the following classroom structures: Task design, Autonomy, Recognition, Grouping, Evaluation, and Time (TARGET). The present study investigated how classroom goal structures as perceived by students…
Biological protective substances in Marthasterias glacialis (Asteroidea) epidermal secretion
1990
Marthasterias glacialis secretes a watery mucous liquid consisting of 14% carbohydrate and 86% protein. The mucous secretion possesses different biological active molecules responsible for lysozyme-like, protease and haemolytic activities. These substances could constitute a molecular barrier playing a protective role against the penetration by bacteria, fungi and parasites. The secretory apparatus consists of two unicellular glands, a large goblet cell and a granular cell, which open directly into the epidermis.
L’architettura gotica in Sicilia centro-orientale nelle perizie degli architetti d’età moderna
2018
L’ARCHITETTURA GOTICA IN SICILIA CENTRO-ORIENTALE NELLE PERIZIE DEGLI ARCHITETTI D’ETÀ MODERNA Il contributo si concentra sulla percezione e sulla valutazione da parte degli architetti siciliani d’età moderna di opere costruite sull’isola in età gotica. L’occasione del confronto emerge soprattutto dalle perizie redatte durante l’elaborazione di nuovi progetti (di ammodernamento, di completamento) che contemplano la salvaguardia o la distruzione delle strutture del passato. Le relazioni selezionate in questa occasione affrontano pertanto questioni di carattere prevalentemente estetico e di linguaggio, ma anche le ragioni inerenti alle strutture e quelle relative alle economie (di cantiere, d…
Tra medioevo e prima età moderna: eclettismi nel Mediterraneo : Ecclettismo consapevole: alcuni casi di approfondimento.
2019
Coexistence and mixture phenomena of different architectural idioms in the early 1500s Sicily are not rare. The present essay evaluates two late Gothic masters, Antonio Belguardo and Girolamo Vicchiuzzo (his epigone), whose activity in Palermo and Alcamo protracts in various and "eclectic" buildings, which go beyond the first half of the XVIth century.
COMPARISON OF CRIMSON FOUNTAINGRASS AND DISS FIBRES AS AGGREGATES FOR CEMENT MORTARS
2019
The use of natural fibres in cement composites is an expanding research field as their use can improve the mechanical and thermal behavior of cement mortars and reduce their carbon footprint. In this paper two different wild grasses, i.e. Pennisetum Setaceum, also known as crimson fountaingrass, and Ampelodesmos Mauritanicus, also called diss, are used as source of natural fibres for cement mortars. The principal aim is to evaluate the possibility of using the more invasive crimson fountaingrass in place of diss inside cement based vegetable concrete. The two plants’ fibres have been characterized by means of electron microscopy, helium picnometry; moreover, the thermal conductivity of fibr…
A stress-responsive miRNA regulates BMP signaling to maintain tissue homeostasis
2021
Adult organisms must sense and adapt to environmental fluctuations. In high-turnover tissues such as the intestine, these adaptive responses require rapid changes in gene expression that, in turn, likely involve posttranscriptional gene control. However, intestinal-tissue-specific microRNA (miRNA)-mediated regulatory pathways remain unexplored. Here, we report the role of an intestinal-specific miRNA, miR-958, that non-cell autonomously regulates stem cell numbers during tissue homeostasis and regeneration in the Drosophila adult midgut. We identify its downstream target cabut, the Drosophila ortholog of mammalian KLF10/11 transcription factors, which mediates this miR-958 function by promo…
Syntheses of (+)-alismoxide and (+)-4-epi-alismoxide.
2006
The first total syntheses of (+)-alismoxide and (+)-4-epi-alismoxide are reported. Formal chemo-, regio-, and stereoselective addition of water to 10alpha-acetoxy-1alphaH,5betaH-guaia-3,6-diene afforded the target compounds after reduction. The absolute stereochemistry of (+)-alismoxide has been established. The low [alpha](D) +8.6 value indicates that significant amounts of alismoxide result from biosynthetic processes. Furthermore, the structure of the natural guaienediol isolated from Silphium perfoliatum has been corrected to (-)-alismoxide.
ScreenPro FH - Screening Project for Familial Hypercholesterolemia in Central, Southern and Eastern Europe: Basic Epidemiology
2017
Uvod: I přes velký pokrok v nedavne době je familiarni hypercholesterolemie (FH) stale jestě celosvětově podceňovane, nedostatecně diagnostikovane, a tedy i nedostatecně lecene onemocněni. O přesne prevalenci pacientů postižených familiarni hypercholesterolemii v regionu středni, východni a jižni Evropy (CESE) mame jen velmi malo informaci. Cilem studie bylo popsat na zakladě dostupných udajů epidemiologickou situaci v regionu CESE. Metody: Vsichni vedouci představitele projektu ScreenPro FH v jednotlivých oblastech byli požadani o poskytnuti lokalnich udajů, ktere se týkaji (a) expertniho odhadu prevalence FH, (b) již fungujicich zdravotnických zařizeni, (c) použitých diagnostických kriter…
ScreenPro FH - Screening project for familial hypercholesterolemia in central, southern and eastern Europe: Rationale and design
2017
Familial hypercholesterolemia (FH) is a genetic disorder with well-known genetic transmission and clinical course. Despite great recent progress, FH is still underestimated, under-diagnosed and thus undertreated. Furthermore it represents a significant healthcare challenge as a common risk factor for the premature development of coronary heart disease. The ScreenPro FH Project is an international network project aiming at improving complex care - from timely screening, through diagnosis to up-to-date treatment of familial hypercholesterolemia in Central, Eastern and Southern Europe. An important task for the project is to harmonise and unify diagnostic and therapeutic approaches in particip…