Search results for "HILIC"

Acid-mediated reaction of bis(pyridine)iodonium(I) tetrafluoroborate with aromatic compounds. A selective and general iodination method

1993

Reaction of aromatic compounds with bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4) in the presence of HBF4 or CF3SO3H in CH2Cl2 at room temperature furnishes monoiodo derivatives with excellent regioselectivity and yields. Use of either acid gives comparable results with activated aromatics, whereas CF3SO3H is much more effective in the iodination of deactivated aromatics. © 1993 American Chemical Society.

Biodiversity, evolution and adaptation of fungi in exstreme environments

2013

Fungi play irreplaceable roles for ecosystem functioning. They may adopt different life styles, for example saprotrophs, symbionts or parasites: some species are cosmopolitan with a wide distribution and others, thanks to they ecological plasticity, may adapt to harsh environments precluded to most of life forms. In stressing conditions, their role is even more crucial for the recycling of organic matter or favouring nutrients uptake. When the conditions become really extreme and competion is low, fungi focus on extremotollerance and evolve peculiar competences to exploit natural or xenobiotic resources in the particular constraints imposed by the environment. This paper focuses on three di…

ChemInform Abstract: Stereoselective Nucleophilic Addition Reactions of Reactive Pseudopeptides.

2010

A new electrophilic addition to acetylenes. Synthesis of 1,2-iodofunctionalized olefins

1986

Abstract Acetylenes react with bis(pyridine)iodo(I) tetrafluoroborate ( 1 ) in the presence of a wide variety of nucleophiles (F, Cl, Br, I, SCN, pyridine, OAc, anisole, H) to give 1,2-iodofunctionalized olefins ( 4 ).

Thyroid neoplasms: surgical and cyto-histopathological connections on a six year cases study

2018

This study aims to evaluate the percentage of cyto-histologic correlation in patients with a thyroid disease documented through clinical-instrumental, cytological (FNAB), histological and surgical examinations. The purpose of this study is also to determine the percentage of disease incidence and evaluating any surgical indication in relation to biological behavior (benign, malignant or indeterminate lesions, occult carcinomas), sex, and age.Almost all of thyroid neoplasms is manifested through thyroid nodule. Therefore, clinical evidence of the thyroid nodule analysis is primarily related to the need to exclude malignant pathology or carcinoma of the thyroid, present in 4-6.5% of cases.The…

Performance of amines as silanol suppressors in reversed-phase liquid chromatography

2016

In reversed-phase liquid chromatography, cationic basic compounds yield broad and asymmetrical peaks, as a result of their ionic interaction with the anionic free silanol groups present in the silica-based stationary phases (commonly derivatised with C18 groups). A simple way to improve the peak shape is the addition to the hydro-organic mobile phase of a reagent (usually called additive) with cationic character. This associates with the stationary phase to prevent the access of analytes to the free silanol groups. Cationic additives may interact electrostatically with the anionic silanols. The hydrophobic region of the additive may also associate with the alkyl chains bound to the stationa…

Enhancing effect of alpha-hydroxyacids on "in vitro" permeation across the human skin of compounds with different lipophilicity.

2005

The percutaneous penetration-enhancing effects of glycolic acid, lactic acid and sodium lauryl sulphate through the human epidermis was investigated using 5-fluorouracil as a hydrophilic model permeant and three compounds belonging to the phenylalcohols: 2-phenyl-ethanol, 4-phenyl-butanol and 5-phenyl-pentanol. The lipophilicity values of the compounds ranged from log Poct -0.95 to 2.89. The effect of the enhancer concentration was also studied. Skin pretreatment with aqueous solutions of the three enhancers did not increase the permeability coefficient of the most lipophilic compound (log Poct = 2.89). For the other compounds assayed, the increase in the permeability coefficients depended …

Epithelioid Hemangioma (Angiolymphoid Hyperplasia With Eosinophilia) of the Heart With Peripheral Eosinophilia and Nephrotic Syndrome

2015

Epithelioid hemangioma (EH) is a rare benign vascular lesion, characterized by endothelial cells with epithelioid/histiocytoid appearance. Heart involvement is extremely rare. We present an unusual case of cardiac EH in a young woman with supraventricular arrhythmia, nephrotic syndrome (membranous glomerulopathy), and peripheral eosinophilia after a pregnancy and normal partum resembling Kimura disease. Echocardiogram showed a large tumor mass in the right cardiac ventricle. The cardiac tumor was removed and the histopathology revealed an endothelial proliferation associated with abundant eosinophils. The neoplastic endothelial cells were eosinophilic and polygonal with epithelioid/histioc…

Lentes de contato corneoesclerais adaptadas em córneas irregulares após cirurgia LASIK

2018

ABSTRACT Purpose: We aimed to describe the outcomes of corneoscleral contact lens fitting with multi-aspherical geometry designs in patients with irregular corneas after laser-assisted in situ keratomileusis (LASIK). Methods: This was a retrospective series of 18 patients (age, 26-38 years) selected from an eye clinic database. Participants were required to have unsatisfactory visual acuity with their current contact lenses or spectacles after LASIK for myopia correction. All patients were fitted with corneoscleral contact lenses designed to correct corneal surface irregularities. A diagnostic trial set was used for fitting, and assessments were performed according to a standardized methodo…

Human pathology in NCL

2013

AbstractIn childhood the neuronal ceroid lipofuscinoses (NCL) are the most frequent lysosomal diseases and the most frequent neurodegenerative diseases but, in adulthood, they represent a small fraction among the neurodegenerative diseases. Their morphology is marked by: (i) loss of neurons, foremost in the cerebral and cerebellar cortices resulting in cerebral and cerebellar atrophy; (ii) an almost ubiquitous accumulation of lipopigments in nerve cells, but also in extracerebral tissues. Loss of cortical neurons is selective, indiscriminate depletion in early childhood forms occurring only at an advanced stage, whereas loss of neurons in subcortical grey-matter regions has not been quantit…