169,773 research outputs found
Composition, spatial distribution and source of floating marine macro litter, in the Northern Tuscan-Corsica marine ecosystem in the Pelagos Sanctuary, monitored along a transborder transect.
No full textResults of four years cetacean monitoring using ferries as platform of research in the northern Tyrrhenian Sea: distribution and spatio-temporal variability
No full text10th International Granulation Workshop
No full textAlthough the wet granulation process can be performed with different equipment, the use of high-shear mixers (HSMs) may offer many advantages. Among these, the most relevant is the possibility of performing all the granulation steps (mixing, wetting, and massing phases) on the same equipment, leading to a reduction in dustiness, risk of cross-contamination, and toxic exposure. However, in general, the drying phase is performed in other equipment to reduce the process time (fluid bed) or the cost (ventilated oven). However, drying can be performed in HSM if the instrument is equipped with a heating jacket and a vacuum pump.
The purpose of this research is to evaluate the effect of the type of drying technique on the properties of granules and tablets. In particular, the two techniques evaluated were drying in a ventilated oven (D-O) or inside the HSG using the heating jacket and vacuum pump (D-J/V). The three formulations selected for this study contain: 40% (w/w) microcrystalline cellulose as granulation aid, 34% (w/w) lactose as diluent, 3% (w/w) polyvinylpyrrolidone K30 as binder, 3% (w/w) sodium starch glycolate as disintegrant and 20% (w/w) of three model molecules as actives (caffeine, paracetamol or citric acid). The actives are characterized by different water solubility and particle size. The study started with a rheological characterization performed using a mixer torque rheometer to identify the amount of water necessary for granulation and to predict the growth mechanism. Granules were produced following a standard procedure and dried in a ventilated oven set at 60°C or inside the HSM using the jacket temperature set at 60°C and a vacuum pressure of 200 mbar. The process was carried out until a LOD of 3% was reached.
As expected, the data highlighted that D-J/V allows for a reduction in drying time ranging from 30 to 45%. The granules were then characterized by sieve analysis (PSD), content uniformity, flowability, tensile strength, and compression studies. The results showed that the granules obtained by D-J/V are generally smaller, with a higher yield and a lower crushing strength. As regards the granule structure, the data and SEM imagines show that the effect of the drying type depends on the solubility of the active; in fact, if the active is very soluble in water, faster migration and crystallization of the active can occur on the granule surface. Granules with a particle size <500 m were then compressed using different compression forces and tablets with a tensile strength of approximately 1 MPa were then characterized by mass and content uniformity tests, disintegration and dissolution tests. Results showed that compressibility, tabletability, and compactability of the granules were improved using D-J/V when the active was sparingly soluble in water, but the disintegration and dissolution performances were not modified. On the contrary, when a highly soluble active is present, D-O allows for an increase of compression properties owing to the crystals present on the surface, but it produces a drastic worsening of disintegration and dissolution performances
Toxicity evaluation of 4-chloro-2-methylphenoxyacetic acid by microtox and comparison with FETAX
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
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