On the convergence to critical scaling profiles in submonolayer deposition models

In this work we study the rate of convergence to similarity profiles in a mean field model for the deposition of a submonolayer of atoms in a crystal facet, when there is a critical minimal size $n\geq 2$ for the stability of the formed clusters. The work complements recently published related results by the same authors in which the rate of convergence was studied outside of a critical direction $x=\tau$ in the cluster size $x$ vs. time $\tau$ plane. In this paper we consider a different similarity variable, $\xi := (x-\tau)/\sqrt{\tau}$, corresponding to an inner expansion of that critical direction, and prove the convergence of solutions to a similarity profile $\Phi_{2,n}(\xi)$ when $x, \tau\to +\infty$ with $\xi$ fixed, as well as the rate at which the limit is approached.Comment: Dedicated to the memory of Jack Car

Rates of convergence to scaling profiles in a submonolayer deposition model and the preservation of memory of the initial condition

We establish rates of convergence of solutions to scaling (or similarity) profiles in a coagulation type system modelling submonolayer deposition. We prove that, although all memory of the initial condition is lost in the similarity limit, information about the large cluster tail of the initial condition is preserved in the rate of approach to the similarity profile. The proof relies in a change of variables that allows for the decoupling of the original infinite system of ordinary differential equations into a closed two-dimensional nonlinear system for the monomer--bulk dynamics and a lower triangular infinite dimensional linear one for the cluster dynamics. The detailed knowledge of the long time monomer concentration, which was obtained earlier by Costin et al. in (O. Costin, M. Grinfeld, K.P. O'Neill and H. Park, Long-time behaviour of point islands under fixed rate deposition, Commun. Inf. Syst. 13, (2), (2013), pp.183-200) using asymptotic methods and is rederived here by center manifold arguments, is then used for the asymptotic evaluation of an integral representation formula for the concentration of $j$-clusters. The use of higher order expressions, both for the Stirling expansion and for the monomer evolution at large times allow us to obtain, not only the similarity limit, but also the rate at which it is approached.Comment: Revised according to referee's suggestions; to be published in SIAM J. Math. Ana

Evaluation of the ability of powdered milk to produce mini-tablets to deliver paracetamol in pediatrics

Paper presented at the 7th International Granulation Workshop. 1-3 July 2015, University of Sheffield, UK"This work aims to evaluate the usefulness of powdered milk as a vehicle of drugs for direct compression into mini-tablets specifically designed for the pediatric population. A 23 full factorial design was carried out to identify the effect of selected variables and their interactions (paracetamol to milk ratio, fraction of disintegrant and compression force), on selected responses (weight variation, thickness and tensile strength of minitablets and dissolution time of paracetamol) of the mini-tablets. Tablets were manufactured according to a matrix design resulting in eight combinations of four different tableting formulations compacted at two distinct forces. Each batch of tablets was evaluated for thickness (n=6), uniformity of weight (n=20), diametric crushing strength and tensile strength (σ) (n=6) and dissolution testing (n=12). A stepwise multiple linear regression was used to identify and quantify the relationships between each response and the variables studied and their interactions. Results were analyzed by ANOVA to identify the significant variables and variable interactions responsible for the effects observed.The increase on milk fraction in the formulation improved the compressibility of paracetamol with a decrease on weight variation. Thinner and harder compacts with slower paracetamol releases were also obtained. These observations were not surprising if powdered milk composition is taken into consideration: milk proteins, lactose (widely used as diluent) and lipids (often used as binders, lubricants and taste masking agents), which individually or in combination contribute to easier the production of tablets. A marked decrease on the dissolution time was observed as sodium croscarmellose was added to the milk rich formulations, as anticipated. The increase of the compression force was reflected by the production of thinner compacts with slightly higher tensile strengths but little effect on the dissolution median time. At high forces it was often observed a higher crushing strength and an increase of the importance of particle deformation in disintegration time.The study has proved the viability of using powdered milk on the production of minitablets to the delivery of drugs. The experimental design and statistical analysis enabled the identification of the most significant variables and their interactions affecting the properties of the mini-tablets, particularly the milk/paracetamol ratio which proved to be critical for the proprieties of the final product."Fundação para a Ciência e Tecnologia (FCT

Effect of different excipients and processing conditions on casein micellar formulation for children

Poster presented at the AAPS Annual Meeting and Exposition (American Association of Pharmaceutical Scientists). October 25-29, 2015, Orlando (FL), USA"Purpose: Investigation of the potential of casein micellar formulations as drug vehicles in pediatrics."Fundação para a Ciência e a Tecnologia (PTDC/DTP-FTO/1057/2012

Evaluation of the ability of powdered milk to produce minitablets containing paracetamol for the paediatric population

The work aims at evaluating the usefulness of powdered milk as a drug matrix for the production of minitablets specifically designed for children. Mixtures made of powdered milk, paracetamol, mannitol, sodium croscarmellose and magnesium stearate (evaluated for flow properties, cohesiveness and caking tendency) were compacted into beams (evaluated for deformation, elasticity and stiffness) and minitablets (evaluated for uniformity of mass, thickness, tensile strength and paracetamol mean dissolution time) and a 23 factorial design performed. The increase on milk fraction in the formulation improved the compressibility of paracetamol and hardness of compacts, reducing weight variation and paracetamol release. A marked decrease on the dissolution time was observed as sodium croscarmellose was added to the milk rich formulations. The increase of the compression force resulted in the production of thinner compacts but had little effect on dissolution time. The production of beams has shown that deformation, bending strength and stiffness increased with both milk and compaction pressure, and decreased with sodium croscarmellose, whereas elasticity decreased when all variables increased. Tensile strength and mean dissolution time described minitablets well, unlike compaction force. The study has proved that powdered milk is suitable for the production of minitablets by direct compression of poor compressible drugs.info:eu-repo/semantics/publishedVersio

Transthoracic single port with peroral assistance : an animal experiment to assess a less invasive technique for human esophageal atresia repair

Prova tipográfica.Thoracoscopic repair of esophageal atresia has becoming the gold standard in many centers since it allows a better cosmetic result and avoids the musculoskeletal sequelae of a thoracotomy. Natural Orifices Transluminal Endocopic Surgery (NOTES) is a new surgical paradigm and its human application was already started in some procedures. In the present study, we explore the feasibility to perform an esophago-esophageal anastomosis using a single transthoracic single port combined with a peroral access in a rabbit model to simulate repair of esophageal atresia by hybrid NOTES in a human newborn. Adult male rabbits (Oryctolagus cuniculus, n=28) were utilized to perform the surgical protocol. We used a transthoracic telescope with a 3 mm working channel and a flexible endoscope with a 2.2 mm working channel by peroral access. We performed total esophagotomy with peroral scissors followed by an esophago-esophageal anastomosis achieved with rigid transthoracic scope helped by peroral operator. Extracorporeal transthoracic knots were performed to complete anastomosis. The anastomoses were examined in loco and ex loco, after animal sacrifice. We successfully accomplished a complete esophageal anastomosis in all rabbits using a combination of transthoracic and peroral 3mm instruments. This study provides important insights for a possible translation of hybrid NOTES to human newborns with esophageal atresia. Forward studies to accomplish their feasibility in human newborns will still be necessary.2010 IPEG Research Gran

LARA as a language-independent aspect-oriented programming approach

Usually, Aspect-Oriented Programming (AOP) languages are an extension of a specific target language (e.g., AspectJ for Java and AspectC++ for C++). This coupling can impose drawbacks such as arbitrary limitations to the aspect language. LARA is a DSL for source-to-source transformations inspired by AOP concepts, and has been designed to be independent of the target language. In this paper we propose techniques to overcome some of the challenges presented by a language-independent approach to source code transformations, and present and discuss possible solutions and their impact. Additionally, we present some of the benefits and opportunities of this approach. We present an evaluation of our approach, show that we can significantly reduce the effort to develop weavers for new target languages and that the proposed techniques contribute to more concise LARA aspects and safer semantics. Copyright 2017 ACM