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In this paper, a methodology to solve radial distribution networks, with constant current and/or impedance loads as well as shunt capacitor banks, is proposed. The techniques currently available to solve such systems are based either on iterative methods or on the bus impedance matrix. In both cases, the elaboration times are quite high since these are related, for iterative methods, to the overall number of iterations, and, for those methods based on the impedance matrix, to the inversion of the admittance matrix. The method developed here is the extension of a technique that is valid to solve networks made of impedances with one supply point. The methodology can also be applied in the solution, with the backward/forward methodology, of meshed systems having voltage-dependent loads and PV nodes. After having described the two cited networks’ analysis methodologies, the new methodology is developed and its implementation is described. The comparison of the computational performances, in terms of CPU times, between the iterative method, the method using the bus impedance matrix and the one developed in this paper provide evidence regarding the efficiency of the latter in strongly reducing the calculation times.

In this paper, a methodology for the load flow solution of distribution systems with fixed voltage nodes (PV nodes) is presented. The proposed technique is the extension of a methodology already set up by the authors to solve distribution systems; it is an iterative approach devoted to the treatment of voltage dependent loads; at each iteration, all the network components (lines, loads, and PV nodes) are represented by resistances and reactances. The methodology is based on the identification of two networks that are solved in sequence, thus allowing the attainment of state features of the original system. One of the two systems is made up only of shunt and series resistances; the other only of shunt and series reactances. If the network is meshed, it is made radial by means of cuts and the injection of currents in the nodes created by the cuts. The unknown features are: the shunt currents in the terminal nodes of the radial or radialized system; the currents injected in the cut nodes of the meshes; and the currents injected in the shunt reactances of the PV nodes. In each of the two systems, all the unknown currents are attained by the solution of a linear system of equations in which all the coefficients of the unknowns and the known terms are deduced, with a backward process, at the branching points of the meshes, at the PV nodes, and at the source node. In the paper, after having recalled the state of the art in the backward/forward methods that are now the most commonly used for distribution systems, the methodology set up by the authors is summarized. Then the PV bus model is illustrated as well as the methodologies for the construction of the matrix of the coefficients of the unknowns and for the construction of the known terms array. Finally, the results of some applications that aim at verifying the speed of convergence and the precision of results are reported.

Chronic osteomyelitis is a surgical disease that require significant dedication from surgeons to eradicate. Osteomyelitis can result from a variety of etiologies but most often is a consequence of trauma (open fractures) to a long bone. This type includes osteomyelitis secondary to a contiguous focus of infection (after trauma and its surgical treatment: osteosynthesis). Here we are reporting one case of post-traumatic chronic osteomyelitis of the humerus.A 34-years-old man presented with a post-traumatic chronic osteomyelitis due to an open fractur of the diaphysis humerus. We proposed a one-step surgical treatment, including fistulectomy, sequestrectomy, opening of the proximal and distal intramedullary canal. Antimicrobial therapy should be followed by close observation and treatment with appropriate antibiotics.A clinical control at 30 days from the intervention revealed that: no secretion; negative cultured exam; second-intention healing of the skin.Treatment requires isolation of the pathogens, significant debridement for removal of all infective and necrotic material, both of bone origin and soft-tissue one. Is is necessary not to close the foci: in this way we leave an external drainage, which is able to provide a tissues sterilization by secretion drainage and by the effects of the systemic antimicrobial therapy. Our results indicate that this long-term problem can be solved by a one-stage procedure that provide spontaneous second- healing of the skin defects, excluding the bony and soft tissue reconstruction.

It is common knowledge that for modern medicine transfusion therapy represents a precious resource and an often mandatory option. It is equally known that autohemotransfusion (or autologous transfusion) provides further advantages: certainty of blood availability when necessary, absence of transfusion reactions, elimination of the risk of infections that is still associated with the traditional homologous transfusions. In its most widespread application, autotransfusion provides for the donation of one or more units of autologous blood, mostly before elective surgery. Even in obstetrics the practice of autologous blood donation with the aim of autotransfusion is finding increasing employment. However, there are still controversial aspects and the need is pointed out for more authoritative verifications as refers to the alleged innocuity to the fetus of acute maternal blood loss. The present study was performed to contribute personal experience to a better definition of the possible interactions between autologous blood donation during pregnancy and unborn child welfare. To this end, 80 term pregnant women underwent fetal heart rate electronic monitoring before, during and after the donation of one unit of autologous blood. Both during and after the phlebotomy there were no cardiotocographic signs of fetal hypo-oxygenation. Even the non stress tests performed at a distance of 24 hours and those that were periodically repeated afterwards were normal, confirming the safety of autologous predonation during pregnancy. However, the authors think that in obstetrics it is still premature to consider the experimental phase of autotransfusion as definitively exhausted.

Autologous blood predonation during pregnancy, with the aim of autotransfusion after delivery, has gained increasing consensus over the last few years. However, there are still some controversial aspects. In particular, the cost/benefit ratio of institutionalizing the above mentioned practice would appear altogether unfavourable (too many women would be really in need of transfusion after delivery). The aim of the present study is to assess the results of our experience using autotransfusion in obstetrics. This longitudinal and prospective study was carried out on a sample of 29 pregnant women who donated 1 unit of blood during the last month of their pregnancy. Phlebotomy was preceded by a verification of the permitting conditions (Hbor = 11 g/dl; Htor = 33%). Before, during and after phlebotomy, the patients underwent cardiotocographic monitoring and periodic observation of vital parameters. The hematologic parameters registered during the various test (before predeposit, before delivery, in puerpery) were statistically analysed. The hemochromo values appeared satisfactory in all cases at the time of admittance for labour. As a consequence of a hematic loss higher than usual at the moment of delivery, in many cases the hemoglobin values during puerpery did not enable us to exclude a priori the advisability of a transfusion. From the study we see how the cost/benefit ratio of the predeposit practice in obstetrics is less unfavourable than commonly thought.

Fetal megalosomia associates with an increased risk of maternal and perinatal pathology. However it is right to make a clear distinction between "physiologic" megalosomia, expression of a high genetic potential of growth from the fetus, and megalosomia referable to any maternal pathology. While the first one entails problems of obstetric management at the most, the second one compels to take measures in order to reduce its incidence. A sample of 45 fetuses with megalosomia was studied retrospectively and compared with a standard sample, randomly selected among the fetuses, term delivered, who in the same period considered (January 1990-January 1994) weighed less than 4 kg at birth. This was done in order to verify which of the risk factors of fetal megalosomia reported in the medical literature affects the most the people who address our Institute. Important risk factors resulted, besides maternal height and postdatism, pre-gestational overweight and obesity. The prognostic significance of the factors, such as advanced maternal age, multiparity, male sex of the unborn child, excessive maternal weight gain during pregnancy, previous megalosomia, was of more difficult interpretation. In our experience, gestational diabetes didn't play the role, universally recognized to it, of the most important risk factor of fetal megalosomia.

Nowadays, a renewed and growing interest is involving the Demand Side Management (DSM) techniques, since they are regarded as suitable tools in Distribution Networks planning. The following drivers trigger off this revitalisation: • The electric demand in urban contexts is growing beyond the expectations, owing to correspondingly increased needs of comfort (air-conditioning, indoor air quality, housekeeping, communication, etc.), which can be fulfilled through the electric end-uses with high quality, compliance with environmental regulations and competitive economic benefits. • This sudden higher pressure of the demand on the local Electric System is bound to force the Distributors to make huge short-term and unforeseen investments for expanding their urban MVLV grids • The use of DSM-based tools and methodologies can slow down the growth rate of the yearly peak load and energy demand. Then, they can supply the planner with cheaper (and likewise efficient) alternatives with respect to a plain grid expansion. The present paper describes the ECORET methodology, the architectures and techniques adopted for it, as well as the obtained results for a case study. ECORET supplies the planners of urban grids with tools for a rational choice among several possible alternative mixes of investments and DSM measures, in order to fulfil the increased demand in an optimal way. The considered approach involves the use of two software packages devoted to grid planning. It is developed through a preliminary screening (which uses a model-generated grid) and of a further analysis on the real grid. Avoided costs for grid expansion are then obtained from this computation and used in the classical DSM economic tests, together with other costs and benefits, to assess the advantages of the considered DSM programmes. The procedure was applied on a case study relevant to a portion of a real urban distribution grid.

ISBN 81-7895-219-X