Stefano Barbero

Vascular Anatomy of the Rectal Stump After Total Mesorectal Excision

PurposeFor many years, poor vascularization of the short rectal stump has been considered the main cause of leakage. The purpose of this study was to evaluate the vascularization of the rectal stump after total mesorectal excision.MethodsWe studied the iliac vascularization on 28 volunteers with healthy rectum to have an anatomic basis. Then, we studied the vascularization of the rectal stumps after total mesorectal excision by using angio computed tomography at seven and three months after operating on 22 patients; we validated this technique by studying the vascularization using angio computed tomography in 18 rectal specimens from cadavers.ResultsBoth in healthy rectums and in rectal stumps after total mesorectal excision, there is good vascularization substained by middle and inferior rectal arteries. The former is more important and frequent as described in previous literature.ConclusionsThe vascularization of the short rectal stump is generally well represented even after total mesorectal excision.

Full length article: Periodic representations and rational approximations of square roots

In this paper the properties of Redei rational functions are used to derive rational approximations for square roots and both Newton and Pade approximations are given as particular cases. As a consequence, such approximations can be derived directly by power matrices. Moreover, Redei rational functions are introduced as convergents of particular periodic continued fractions and are applied for approximating square roots in the field of p-adic numbers and to study periodic representations. Using the results over the real numbers, we show how to construct periodic continued fractions and approximations of square roots which are simultaneously valid in the real and in the p-adic field.

On the operations of sequences in rings and binomial type sequences

Given a commutative ring with identity R, many different and interesting operations can be defined over the set

Groups and monoids of Pythagorean triples connected to conics

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Colored compositions, Invert operator and elegant compositions with the ''black tie''

HR of sequences of elements in R. These operations can also give

Endovascular Solution for Incorrect Stent Positioning

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