Pancreatoscopy-guided electrohydraulic lithotripsy in a patient with calcific chronic pancreatitis

info:eu-repo/semantics/publishedVersio

Endometriosis: A Rare Cause of Large Bowel Obstruction.

Large bowel obstruction can result in significant morbidity and mortality, especially in cases of acute complete obstruction. There are many possible causes, the most common in adults being colorectal cancer. Endometriosis is a benign disease, and the most affected extragenital location is the bowel, especially the rectosigmoid junction. However, transmural involvement and acute occlusion are very rare events. We report an exceptional case of acute large bowel obstruction as the initial presentation of endometriosis. The differential diagnosis of colorectal carcinoma may be challenging, and this case emphasizes the need to consider intestinal endometriosis in females at a fertile age presenting with gastrointestinal symptoms and an intestinal mass causing complete large bowel obstruction.info:eu-repo/semantics/publishedVersio

Antracnose em hortaliças da família solanacea.

bitstream/CNPH-2010/36354/1/ct-79.pd

Natural-origin polymers as carriers and scaffolds for biomolecules and cell delivery in tissue engineering applications

The present paper intends to overview a wide range of natural–origin polymers with special focus on proteins and polysaccharides (the systems more inspired on the extracellular matrix) that are being used in research, or might be potentially useful as carriers systems for active biomolecules or as cell carriers with application in the tissue engineering field targeting several biological tissues. The combination of both applications into a single material has proven to be very challenging though. The paper presents also some examples of commercially available natural–origin polymers with applications in research or in clinical use in several applications. As it is recognized, this class of polymers is being widely used due to their similarities with the extracellular matrix, high chemical versatility, typically good biological performance and inherent cellular interaction and, also very significant, the cell or enzyme-controlled degradability. These biocharacteristics classify the natural–origin polymers as one of the most attractive options to be used in the tissue engineering field and drug delivery applications

Regularized covariance estimation for weighted maximum likelihood policy search methods

Many episode-based (or direct) policy search algorithms, maintain a multivariate Gaussian distribution as search distribution over the parameter space of some objective function. One class of algorithms, such as episodic REPS, PoWER or PI2 uses, a weighted maximum likelihood estimate (WMLE) to update the mean and covariance matrix of this distribution in each iteration. However, due to high dimensionality of covariance matrices and limited number of samples, the WMLE is an unreliable estimator. The use of WMLE leads to over-fitted covariance estimates, and, hence the variance/entropy of the search distribution decreases too quickly, which may cause premature convergence. In order to alleviate this problem, the estimated covariance matrix can be regularized in different ways, for example by using a convex combination of the diagonal covariance estimate and the sample covariance estimate. In this paper, we propose a new covariance matrix regularization technique for policy search methods that uses the convex combination of the sample covariance matrix and the old covariance matrix used in last iteration. The combination weighting is determined by specifying the desired entropy of the new search distribution. With this mechanism, the entropy of the search distribution can be gradually decreased without damage from the maximum likelihood estimate

Influence of the porosity of starch-based fiber mesh scaffolds on the proliferation and osteogenic differentiation of bone marrow stromal cells cultured in a flow perfusion bioreactor

This study investigates the influence of the porosity of fiber mesh scaffolds obtained from a blend of starch and poly(!-caprolactone) on the proliferation and osteogenic differentiation of marrow stromal cells cultured under static and flow perfusion conditions. For this purpose, biodegradable scaffolds were fabricated by a fiber bonding method into mesh structures with two different porosities– 50 and 75%. These scaffolds were then seeded with marrow stromal cells harvested from Wistar rats and cultured in a flow perfusion bioreactor or in 6-well plates for up to 15 days. Scaffolds of 75% porosity demonstrated significantly enhanced cell proliferation under both static and flow perfusion culture conditions. The expression of alkaline phosphatase activity was higher in flow cultures, but only for cells cultured onto the higher porosity scaffolds. Calcium deposition patterns were similar for both scaffolds, showing a significant enhancement of calcium deposition on cellscaffold constructs cultured under flow perfusion, as compared to static cultures. Calcium deposition was higher in scaffolds of 75% porosity, but this difference was not statistically significant. Observation by scanning electron microscopy showed the formation of pore-like structures within the extracellular matrix deposited on the higher porosity scaffolds. Fourier transformed infrared spectroscopy with attenuated total reflectance and thin-film X-ray diffraction analysis of the cell-scaffold constructs after 15 days of culture in a flow perfusion bioreactor revealed the presence of a mineralized matrix similar to bone. These findings indicate that starch-based scaffolds, in conjunction with fluid flow bioreactor culture, minimize diffusion constraints and provide mechanical stimulation to the marrow stromal cells, leading to enhancement of differentiation toward development of bone-like mineralized tissue. These results also demonstrate that the scaffold structure, namely, the porosity, influences the sequential development of osteoblastic cells and, in combination

The relationship between the effective tax rate and the nominal rate

The main goal of this investigation is to understand the relationship between the nominal rate and the effective tax rate and to evaluate if the differences between them depend on the value of the nominal rate. Based on a sample of 1,530 companies from 5 countries members of the European Union (Denmark, Slovenia, Finland, Luxembourg and the United Kingdom) there’s evidence that the effective tax rate is positively related to the nominal rate. The effective tax rate was calculated through the ratio between the value of the tax paid over the result before tax. When the nominal tax rate increases, the effective rate increases equally but with a slower growth. This relationship is softened if we take into account the value of the nominal tax rate, which shows that companies have the ability to manage the results in order to increase savings in tax.info:eu-repo/semantics/publishedVersio