Search results for "NOAC"

Identification of carbonate-rich outcrops on Mars by the Spirit rover.

2010

Ancient Carbonate Minerals on Mars The historical presence of liquid water on Mars together with a CO 2 -rich atmosphere should have resulted in the accumulation of large deposits of carbonate minerals. Yet, evidence for the presence of carbonates on the surface of Mars has been scarce. Using data collected by the Mars Exploration Rover, Spirit, Morris et al. (p. 421 , published online 3 June; see the Perspective by Harvey ) now present evidence for carbonate-rich outcrops in the Comanche outcrops within the Gusev crater. The carbonate is a major outcrop component and may have formed in the Noachian era (∼4 billion years ago) by precipitation from hydrothermal solutions that passed through …

Preparation, characterization and in vitro antimicrobial activity of ampicillin-loaded polyethylcyanoacrylate nanoparticles.

1998

In this paper, the experimental conditions for preparing ampicillin-loaded polyethylcyanoacrylate (PECA) nanoparticles are described. The effects of drug concentration and surfactant type in the polymerization medium on the particle size distribution and loading capacity were studied. The results of these studies show that only the type of surfactant has an impact on the nanoparticle dimensions. The release rate of ampicillin from PECA nanoparticles at pH 7.4 (extracellular value pH) performed either with and without esterases, show that the drug release is considerably increased in the presence of these exzymes. The results of drug release study at pH 1.1 (simulated gastric juice) are very…

Multifunctional derivatives of dimethoxy-substituted triphenylamine containing different acceptor moieties

2020

This project has received funding from the Research Council of Lithuania (LMTLT), Agreement No. [S-LZ-19-2]. This research was funded by the Région Centre, the Tunisian ministry of research, University of Monastir and the French ministry of Higher Education and Research. J. Bouclé would like to thank the Sigma-Lim LabEx environment for financial supports, and the PLATINOM facility at XLIM laboratory regarding device fabrication and characterizations. DG acknowledges the Lithuanian Academy of Sciences for the financial support.

Amoxicillin-loaded polyethylcyanoacrylate nanoparticles: influence of PEG coating on the particle size, drug release rate and phagocytic uptake.

2001

Polyethyleneglycol (PEG)-coated polyethylcyanoacrylate (PECA) nanoparticles loaded with amoxicillin were prepared and the influence of the PEG coating on the particle size, zeta potential, drug release rate and phagocytic uptake by murine macrophages was studied. Experimental results show that this colloidal drug delivery system could be useful for intravenous or oral administration. The profile of amoxicillin release from PECA nanoparticles system was studied under various conditions similar to those of some corporeal fluids. In all these experiments, amoxicillin release in the free form was studied by HPLC analysis. Experimental results showed that at pH 7.4 drug release rises when molecu…

Evaluation of polyalkylcyanoacrylate nanoparticles as a potential drug carrier: preparation, morphological characterization and loading capacity.

1993

Some physicochemical behaviours were investigated of polyethyl- (PECA) and polyisobutylcyanoacrylate (PICA), which, in recent years, have been proposed as nanoparticle colloidal systems for drug carrying. We observed the influence of preparation conditions, such as pH value and surfactant concentration, on parameters such as particle size and polymer molecular weight. Lower operating pH values (0-2) resulted in smaller nanoparticles than those prepared at pH 5.5. The polymer molecular weight was also a function of pH: low molecular weight at low pH and vice-versa. The surfactant concentration positively influenced main particle size and polymer molecular weight. These trends were independen…

Guanidinoacetate-creatine in secondary progressive multiple sclerosis: a case report.

2022

Acute secondary progressive multiple sclerosis (SPMS) is characterized by escalating neurological disability, with limited disease-modifying therapeutic options. A 48-year-old woman with acute SPMS being treated with interferon beta-1a and oral corticosteroids presented as a clinical outpatient with no disease-modifying effects after treatment. A decision was made to treat her with a combination of guanidinoacetate and creatine for 21 days. She had made clinical progress at follow-up, with the intensity of fatigue dropping from severe to mild. Magnetic resonance spectroscopy revealed increased brain choline, creatine, N-acetylaspartate, and glutathione. Patients with SPMS may benefit from …

Diverse Lithologies and Alteration Events on the Rim of Noachian‐Aged Endeavour Crater, Meridiani Planum, Mars: In Situ Compositional Evidence

2018

We report the results of geological studies by the Opportunity Mars rover on the Endeavour Crater rim. Four major units occur in the region (oldest to youngest): the Matijevic, Shoemaker, Grasberg, and Burns formations. The Matijevic formation, consisting of fine‐grained clastic sediments, is the only pre‐Endeavour‐impact unit and might be part of the Noachian etched units of Meridiani Planum. The Shoemaker formation is a heterogeneous polymict impact breccia; its lowermost member incorporates material eroded from the underlying Matijevic formation. The Shoemaker formation is a close analog to the Bunte Breccia of the Ries Crater, although the average clast sizes are substantially larger in…

Nature and origin of the hematite-bearing plains of Terra Meridiani based on analyses of orbital and Mars Exploration rover data sets

2006

The ~5 km of traverses and observations completed by the Opportunity rover from Endurance crater to the Fruitbasket outcrop show that the Meridiani plains consist of sulfate-rich sedimentary rocks that are largely covered by poorly-sorted basaltic aeolian sands and a lag of granule-sized hematitic concretions. Orbital reflectance spectra obtained by Mars Express OMEGA over this region are dominated by pyroxene, plagioclase feldspar, crystalline hematite (i.e., concretions), and nano-phase iron oxide dust signatures, consistent with Pancam and Mini-TES observations. Mossbauer Spectrometer observations indicate more olivine than observed with the other instruments, consistent with preferentia…

Sortase A Inhibitors: Recent Advances and Future Perspectives

2015

Here, we describe the most promising small synthetic organic compounds that act as potent Sortase A inhibitors and cater the potential to be developed as antivirulence drugs. Sortase A is a polypeptide of 206 amino acids, which catalyzes two sequential reactions: (i) thioesterification and (ii) transpeptidation. Sortase A is involved in the process of bacterial adhesion by anchoring LPXTG-containing proteins to lipid II. Sortase A inhibitors do not affect bacterial growth, but they restrain the virulence of pathogenic bacterial strains, thereby preventing infections caused by Staphylococcus aureus or other Gram-positive bacteria. The efficacy of the most promising inhibitors needs to be com…

Composizione aminoacidica degli occhi di piccoli pesci pelagici in relazione ai processi oceanografici negli habitat di deposizione

Studio della valutare della composizione aminoacidica degli occhi di piccoli pesci pelagici in relazione ai processi oceanografici negli habitat di deposizione. La scelta di proporre uno studio sulla composizione aminoacidica degli occhi di E. encrasicolus è stata suggerita da studi pregressi che ne hanno evidenziato la specificità alla specie. In particolare, le misurazioni morfometriche e le analisi della composizione aminoacidica (AAC), degli enzimi, dei lipidi e carboidrati effettuati sulle larve di acciuga, hanno permesso di valutare se le diverse caratteristiche ambientali delle due aree possono influenzare le larve di Engraulis encrasicolus all’interno del Canale di Sicilia. Si tratt…