Search results for "Configuration"

Terpioside B, a difucosyl GSL from the marine sponge Terpios sp. is a potent inhibitor of NO release.

2010

Terpioside B (2a), a unique glycolipid containing two fucose residues in the furanose form in its pentasaccharide chain, was isolated from the marine sponge Terpios sp. Its complete stereostructure was solved by interpretation of mass spectrometric and NMR data along with CD and GG-MS analyses of its degradation products. Terpioside B is a potent inhibitor against LPS-induced NO release, and is considerably more active than simpler glycosphingolipids such as terpioside A and monoglucosylceramide.

Stereochemistry of terpene derivatives. Part 3: Hydrolytic kinetic resolution as a convenient approach to chiral aminohydroxyiminocaranes with local …

2002

Abstract We have developed a stereoselective hydrolytic kinetic resolution process for diastereoisomeric mixtures of epoxyiminocarene intermediates in the presence of ( R , R )-(−)-(salen)Co(III)OAc catalyst, this was applied as the first step in the synthesis of novel chiral aminohydroxyiminocarane derivatives with local anaesthetic activity. The absolute configuration of the product was confirmed by X-ray crystallography.

Experimental and numerical analysis on post welding formability of FSWed AZ31 magnesium alloy thin joints obtained using a "Pinless" tool configurati…

2012

The post welding formability of friction stir welded AZ31 magnesium alloy thin sheets (1.5 mm thick), obtained using a “pinless” tool configuration, was widely investigated by means of the hemispherical punch method at 350°C, with a constant crosshead speed of 0.1 mm/s. The results were compared with those obtained on the base material. It has shown that formability of the joints is lower than the one of the base material. The experimental work was supported by a numerical investigation based on FEM in order to highlight the material flow occurring during the welding process. Additionally, hemispherical punch tests were simulated starting from the calculated conditions, in terms of accumula…

Experimental and numerical analysis on FSWed magnesium alloy thin sheets obtained using “pin” and “pinless” tool

2012

Acid rearrangment of epoxy-germacranolides and absolute configuration of 1beta, 10alpha-epoxy-salonitenolide

2010

The acid-catalyzed cyclization of mono epoxides of cnicin acetonide (3) was investigated. Several 6,12-eudesmanolides were obtained, and their stereochemistry established by extensive spectroscopic analyses. Chemical correlations also led to the assignment of the absolute configuration of 1beta,10alpha-epoxy-salonitenolide (13), a previously isolated natural product. The cytotoxic activities of some compounds were determined against A549 and MCF-7 tumor cell lines. The esterified germacranolides 2-6 were selectively cytotoxic against the MCF-7 breast cancer cell line.

A New Cacospongionolide Inhibitor of Human Secretory Phospholipase A2 from the Tyrrhenian Sponge Fasciospongia cavernosa and Absolute Configuration o…

1998

A new inhibitor of human secretory phospholipase A2 (PLA2), cacospongionolide E (4a), has been isolated from the Tyrrhenian sponge Fasciospongia cavernosa. The structure was proposed on the basis of spectroscopic data and by chemical transformations. The absolute configuration of cacospongionolides 2a-4a was established using the modified Mosher's method. Cacospongionolide E was the most potent inhibitor toward human synovial PLA2, showing higher potency than the reference compound manoalide and exerting no signs of toxicity on human neutrophils. It showed high activity in the Artemia salina bioassay and moderate toxicity in the fish (Gambusia affinis) lethality assay.

Sesquiterpenoids from the Endophytic Fungus Rhinocladiella similis

2019

Ten new sesquiterpenoid derivatives, rhinomilisins A-J (1-10), along with six known analogues (11-16), were isolated from the mangrove-derived endophytic fungus Rhinocladiella similis. The structures of the new compounds were elucidated by their NMR and MS data, while the absolute configuration of 3 and 6 was determined by X-ray crystallographic analysis and Mosher's method, respectively. All isolated compounds (1-16) were evaluated for their cytotoxicity against the mouse lymphoma cell line L5178Y, and compounds 1, 7, and 15 showed moderate activity with IC50 values of 5.0, 8.7, and 24.4 μM, respectively.

Metal-Controlled Magnetoresistance at Room Temperature in Single-Molecule Devices

2017

The appropriate choice of the transition metal complex and metal surface electronic structure opens the possibility to control the spin of the charge carriers through the resulting hybrid molecule/metal spinterface in a single-molecule electrical contact at room temperature. The single-molecule conductance of a Au/molecule/Ni junction can be switched by flipping the magnetization direction of the ferromagnetic electrode. The requirements of the molecule include not just the presence of unpaired electrons: the electronic configuration of the metal center has to provide occupied or empty orbitals that strongly interact with the junction metal electrodes and that are close in energy to their F…

Qualitative differences in the exploration of upright and upside-down faces in four-month-old infants : An eye-movement study

2006

The goal of this study was to test if apprentice readers (6-7 to 7-8 years old) and beginner readers (8-9 to 10-11 years old) perceive syllabic units in written words. The paradigm of illusory conjunctions was used because it can determine the infra-lexical units identified at the first steps of the written stimuli process. Two experiments were conducted on children from the first (6-7 years old) to the last years (10-11 years old) of the learning-to-read process. Results have shown that children perceive syllables in letter sequences as soon as the end of the first year of the learning-to-read process. The perception of these units is the result of two information sources: the syllabic pho…

Objectively Measured Physical Activity and Changes in Life-Space Mobility Among Older People

2015

Background Our aim was to study the relationship between objectively measured physical activity and subsequent changes in life-space mobility over 2 years among older people. Life-space mobility refers to the area a person moves through in daily life, taking into account frequency, and need of assistance. Life-space mobility and physical activity correlate, but whether different intensities of objectively assessed physical activity predicts decline in life-space mobility is not known. Methods Prospective cohort study of the "Life-space Mobility in Old Age" (LISPE) project accelerometer substudy. Participants were community-dwelling older people aged 75-90 (n = 164). Life-space mobility was …