104 research outputs found

    Adnexal Torsion in Pediatric Age: Does Bolli's Score Work? Report of Two Cases

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    Adnexal torsion is a surgical emergency requiring early diagnosis in order to avoid demolitive surgery. Adnexal torsion's diagnosis could be very difficult in pediatric patients because children cannot explain symptoms accurately. Furthermore reproductive organs lie high in abdomen, causing unclear examinations findings. For reducing diagnostic mistakes or delay clinical and hematological criteria could be useful. No radiological criteria (CT or MRI) should be taken in count because of the costs and the required time. By combining clinical presentation in patients with OT three useful diagnostic variables have been identified: age, duration of pain, vomiting. Presence of vomiting, short duration of abdominal pain and high CRP levels have great predictive value for the diagnosis of adnexal torsion. In those patients an exploratory laparoscopy should be performed without any doubt and/or delay. These data may aid physicians in the evaluation of abdominal pain in premenarchal girls

    Heterogeneous structures studied by interphase elasto-damaging model.

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    For all structures that are constituted by heterogeneous materials, the meso-modelling approach is the most rigorous since it analyzes such structures as an assembly of distinct elements connected by joints, the latter commonly simulated by apposite interface models. In particular, the zero-thickness interface (ZTI) models are extensively used in those cases where the joint thickness is small if compared to the other dimensions of the heterogeneosu material. In ZTI models the constitutive laws relate the contact tractions to the displacement discontinuities at the interface, but in many cases the joint response depends also on internal stresses and strains within the bulkmaterial. In this sense the interphase model represents an enhancement of the ZTI because is able to introduce the effect of internal stresses into the analysis. Particular attention is spent to the definition of a damage model in order to describe the propagation of a fracture inside the interphase element. The damage model is developed in a thermodinamically context for plane stress applications

    Elastoplastic Damaging Model for Adhesive Anchor Systems. II: Numerical and Experimental Validation

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    This paper presents the numerical and experimental validation of the analytical elastoplastic damaging model proposed in the companion paper (Part I). The validation was carried out by describing the pullout failure of epoxy adhesive anchors. Pullout tests were simulated numerically and performed experimentally. Several specimens made of a rebar embedded in a hardened concrete cylinder by means of polyester resin were tested. Conventional strain gauges and acoustic emission (AE) sensors were used to evaluate the structural response of the system and to monitor the onset and progression of structural damage, respectively. The parametric analysis and the moment tensor analysis of the AE data were used to discriminate among different sources of damage. The results show the ability of the model to predict the response of the anchors and the suitability of the AE method to monitor damage onset and propagation and to discriminate among different source of damage

    An Euler-Bernoulli beam element with lumped plasticity applied on RC framed structures

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    Most of existing reinforced concrete structures suffer due to corrosion of steel and concrete degradation. In many cases existing structures reveal to be inadequate to absorb the expected seismic load and need to be rehabilitated according to the in force code. In the worst case some structures have not been designed to absorb horizontal actions. The rehabilitation process begins with the complete knowledge of its geometrical configuration and the evaluation of the vulnerability of the structure to seismic loads. This analysis permits to identify critical zones and to establish focused strengthening actions. A comparison between the behavior of the structure in the current and in the future configurations determines the goodness of adopted intervention techniques. The evaluation of the vulnerability of an RC structure to seismic loads can be done by performing nonlinear finite element analyses. In literature, three different approaches have been tuned to simulate the elastoplastic behavior of a beam/column element: lumped elastoplasticity models, distributed nonlinearity models, fiber models. Lumped models consider the constitutive nonlinearity concentrated at a section level of a frame element, usually employing nonlinear springs at the ends of beam/column elements. Distributed nonlinearity models average the nonlinearity over a finite element by considering the possibility to form plastic hinges at different evaluation points of the element and calculating weighted integrals of the section responses. Fiber models subdivide a section with a large number of finite elements and nonlinearity is related to the stress-strain relationship of a single finite element. Within lumped models, commercial finite element programs contemplate the possibility to develop plasticity at the two ends of the beam only. In the particular cases where plasticity concentrates in points different than the ends of the beam, it computationally comes in the need to proceed with a re-meshing of the model or in the definition of multiple elements before running the analysis. In the first case, it results in an increased computational cost of the analysis. In the second case, a less precision of the response is obtained especially when the exact position of the plastic hinge is not a-priori known. The present work is devoted to the implementation of a new elastoplastic 3D Euler-Bernoulli beam element including slope discontinuities, in the framework of lumped elastoplasticity models. In the new finite element, plastic hinges can appear at any position of the beam, theoretically in a priori not-established number. Multiple slope discontinuities are included in the analysis through a non uniform bending stiffness of the beam, making use of the Dirac-delta function. Fictitious springs, with a stiffness variable according to the level of plasticity in the section, transfer the correct bending moment in correspondence of plastic hinges.The nonlinear behavior of the hinge is defined in the framework of a thermo-dynamically consistent elastoplastic theory. Associated flow rules are derived in the classical manner adopting a convex activation domain known in literature and experimentally calibrated for reinforced concrete sections. The activation domain is similar to the one suggested by the Italian seismic code. It is given in a My-Mz bending moment reference system for a fixed axial force. An elastoplastic behavior is assumed for section curvatures, while deformations in the axial and shear directions are assumed elastic. The elastoplastic frame element is introduced in a finite element analysis program to run nonlinear simulations on 2D and 3D framed structures. To this end, state equations and flow rules are rewritten in a discrete manner to solve the single iteration of the Newton-Raphson procedure. A classic elastic predictor phase is followed by a plastic corrector phase in the case of activation of the inelastic phenomena. The corrector phase is based on the evaluation of return bending moments by employing the closest point projection method, in order to satisfy the loading-unloading conditions (Kuhn-Tucker relations). The formation of one or more hinges inside a finite element modifies the distribution of internal forces and its stiffness matrix. As a consequence, the global stiffness matrix is continuously modified at each plastic load step until it becomes singular. Numerical examples are furnished as validation tests of the program. The efficiency of the proposed model is demonstrated comparing the results with those available in literature

    S-100a0 protein stimulates Ca2+ -induced Ca2+ release from isolated sarcoplasmic reticulum vesicles

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    AbstractS-100a0 protein, the αα-isoform of the S-100 family, stimulates Ca2+ -induced Ca2+ release from terminal cisternae isolated from rat skeletal muscle cells. The stimulatory effect of S-100a0 is maximal at ∼5 μM S-100a0 and half maximal at ∼0.1 μM S-100a0, at 1.8 μM free Ca2+ in the presence of 5 mM Mg2+ plus 0.1 M KCl. The effect of the protein on Ca2+ -induced Ca2+ release is completely inhibted by the calcium release blocker, ruthenium red

    MOLECULAR CHARACTERIZATION OF K26 GENE OF LEISHMANIA INFANTUM, ISOLATE BY HUMAN PATIENTS FROM SICILY REGION

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    Human Leishmaniasis is an emerging problem in Italy and increase in the Sicily region. In the present work, we explored the genetic polymorphism of Leishmania isolates from twenty-five cases of human Leishmaniasis: two cases of visceral Leishmaniasis (VL) and twenty-three of cutaneous Leishmaniasis (CL). The characterization is carried out in comparison with twenty five human isolates of leishmania and one reference strain, L. infantum MHOM/TN/80IPT1 (MON-1). MON-1 is the most common zymodeme responsible for Leishmaniasis in Italy. The aim of the study is to genotype Leishmania isolates from Sicily by PCR ,analyzing size polymorphism of K26 gene to discriminate between MON-1 and non MON-1 zymodemes. K26 is a protein belonging to the Hydrofilic acylated surface protein B (HASPB) family. It is characterized by repeated aminoacidal domains and shows polymorphisms. The k26 polymorphism of MON-1 zymodeme is determinate in the size of 626 bp. The analysis show that all the 25 isolates belong to the L. infantum species, in particular the product size of 626 bp is detect in six patients affected by cutaneous Leishmaniasis. The molecular tools applied in this study can constitute a helpful support for parasite tracking and for a better understanding of the epidemiological evolution of Leishmaniasis

    Kidney transplantation from living donor with monolateral renal artery fibromuscular dysplasia using a cryopreserved iliac graft for arterial reconstruction: a case report and review of the literature

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    Background Aging and mortality of patients on waiting lists for kidney transplantation have increased, as a result of the shortage of organs available all over the world. Living donor grafts represent a significant source to maintain the donor pool, and resorting successfully to allografts with arterial disease has become a necessity. The incidence of renal artery fibromuscular dysplasia (FMD) in potential living renal donors is reported to be 2-6%, and up to 4% of them present concurrent extra-renal involvement. Case presentation We present a case of renal transplantation using a kidney from a living donor with monolateral FMD. Resection of the affected arterial segment and its subsequent replacement with a cryopreserved iliac artery graft from a deceased donor were performed. No intraoperative nor post-operative complications were reported. The allograft function promptly resumed, with satisfying creatinine clearance, and adequate patency of the vascular anastomoses was detected by Doppler ultrasounds. Conclusion Literature lacks clear guidelines on the eligibility of potential living renal donors with asymptomatic FMD. Preliminary assessment of the FMD living donor should always rule out any extra-renal involvement. Whenever possible, resection and reconstruction of the affected arterial segment should be taken into consideration as this condition may progress after implantation
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