Search results for "Sorption"

In Vitro Percutaneous Penetration of Acyclovir from Solvent Systems and Carbopol 971-P Hydrogels: Influence of Propylene Glycol

2005

The mechanism underlying propylene glycol (PG) effects on acyclovir (ACV) penetration through human epidermis were studied. Solvent systems and Carbopol gels containing increasing percentage of PG (from 0% to 70%, w/w) were used. Viscosity studies of both vehicles were carried out to characterise the influence of rheological behaviour. In solvent systems skin permeation values of ACV increase as the concentration of PG increase yielding a maximum enhancement ratio (ER = 10) for 70% PG. The release rate of ACV from gels was determined. Higuchi's model was used to estimate the apparent diffusion coefficient of the drug. These values show a decrease as the content of PG in the vehicle increase…

Enhancement of nortriptyline penetration through human epidermis: influence of chemical enhancers and iontophoresis.

2008

Abstract Different known percutaneous chemical enhancers and iontophoresis have been tested in-vitro to study their ability to increase transdermal absorption of nortriptyline hydrochloride (20 mg mL−1). The chemicals 1-dodecanol, Span 20, Azone, (R)-(+)-limonene or isopropyl myristate were used as an overnight pretreatment at 5% (w/w) in ethanol. Furthermore, isopropyl myristate (20%, w/w) and propylene glycol (15%, w/w) were tested in the same vehicle. Iontophoresis was applied directly to the nortriptyline hydrochloride donor solution for three different concentrations (20, 2 and 0.5 mgmL−1). The chemical enhancers slightly increased the nortriptyline transdermal flux but iontophoresis w…

Photobleaching effects onin vivoskin autofluorescence lifetime

2015

The autofluorescence lifetime of healthy human skin was measured using excitation provided by a picosecond diode laser operating at a wavelength of 405 nm and with fluorescence emission collected at 475 and 560 nm. In addition, spectral and temporal responses of healthy human skin and intradermal nevus in the spectral range 460 to 610 nm were studied before and after photobleaching. A decrease in the autofluorescences lifetimes changes was observed after photobleaching of human skin. A three-exponential model was used to fit the signals, and under this model, the most significant photoinduced changes were observed for the slowest lifetime component in healthy skin at the spectral range 520 …

Efficacy of a bioactive alloplast, in the treatment of human periodontal osseous defects-a clinical study.

2010

Presently, bone replacement grafts are one of the modalities of therapy for which there is histologic evidence of regeneration coronal to the base of the previous osseous defect. Bioactive glasses are used extensively in medicine and dentistry. This study evaluated the additional efficacy of a bioactive alloplast, PerioGlas, in comparison with open flap debridement only. 8 systemically healthy volunteers were chosen, each having 2 collateral sites with ?6 mm clinical probing depth and radiographic evidence of an intrabony defect. Randomly, one defect was treated with open flap debridement plus bioactive glass (test) and the other with open flap debridement alone (control). At baseline, 3, 6…

The effect of cathartic agents on transmucosal electrical potential difference in the human rectum.

1980

Active ion transport in the colon is generating a transmucosal electrical potential difference (PD) of about 40 mV. Cathartic agents inhibit electrolyte and water net-absorption or cause net-secretion which should be reflected in a change of PD. In 83 normal subjects the effect of an isotonic eletrolyte solution (control) and different cathartic agents on rectal PD was tested: Laxatives (bisacodyl, rhein), bile acids (cholic and deoxycholic acid), fatty acids (oleic and ricinoleic acid) and cardiac glycosides (meproscillarin, digitoxin, digoxin). Bisacodyl, deoxycholic acid in high concentration, meproscillarin and digitoxin significantly decreased PD, while the other substances did not. Ca…

CARDIAC PUNCTURE OF FETUS WITH HURLER'S DISEASE AVOIDING ABORTION OF UNAFFECTED CO-TWIN

1978

Plasma non-cholesterol sterols in primary hypobetalipoproteinemia

2011

Primary hypobetalipoproteinemia (pHBL) is characterized by plasma cholesterol levels ApoB48, and FHBL harbouring as yet unknown molecular defects. Not linked FHBL kindred are not homogeneous in terms of plasma NCS levels. NCS cannot replace genetic HBL analysis.

Synergism between exposure to mercury and use of iodine supplements on thyroid hormones in pregnant women

2015

Objective: To evaluate the association between mercury exposure and thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and free thyroxine (FT4) levels during pregnancy as well as to explore if there is any synergic action between mercury and intake of iodine from different sources. Methods: The study population was 1407 pregnant women participating in the Spanish INMA birth cohort study. Total mercury concentrations were analyzed in cord blood. Thyroid hormones (THs) were measured in serum samples collected at 13.2 +/- 1.5 weeks of gestation. The association between mercury and TH levels was evaluated with multivariate linear regression models. Effect modification caused by iod…

Aerosol properties of the Eyjafjallajökull ash derived from sun photometer and satellite observations over the Iberian Peninsula

2012

The Eyjafjallajökull ash that crossed over Spain and Portugal on 6e12 May 2010 has been monitored by a set of operational sun photometer sites within AERONET-RIMA and satellite sensors. The sun photometer observations (aerosol optical depth, coarse mode concentrations) and ash products from IASI and SEVIRI satellite sensors, together with FLEXPART simulations of particle transport, allow identifying the volcanic aerosols. The aerosol columnar properties derived from inversions were investigated, indicating specific properties, especially regarding the absorption. The single scattering albedo was high (0.95 at 440 nm) and nearly wavelength independent, although with slight decrease with wave…

Water-Insoluble Organics Dominate Brown Carbon in Wintertime Urban Aerosol of China: Chemical Characteristics and Optical Properties.

2020

The chromophores responsible for light absorption in atmospheric brown carbon (BrC) are not well characterized, which hinders our understanding of BrC chemistry, the links with optical properties, and accurate model representations of BrC to global climate and atmospheric oxidative capacity. In this study, the light absorption properties and chromophore composition of three BrC fractions of different polarities were characterized for urban aerosol collected in Xi'an and Beijing in winter 2013-2014. These three BrC fractions show large differences in light absorption and chromophore composition, but the chromophores responsible for light absorption are similar in Xi'an and Beijing. Water-ins…