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Introduction: Globally, many regions have an urgent, unmet need of neurosurgical care. A multi-step neurosurgical twinning technique, International Neurosurgical Twinning Modeled for Africa (INTIMA), was proved to be successful during a previous mission to Neurosurgical Unit, Enugu, Nigeria. The Swedish African Neurosurgical Collaboration (SANC) performed a developmental mission together with the local neurosurgical unit in The Gambia, adopting the INTIMA model. Methods: A multidisciplinary team visited for a 2-week collaborative mission at the Neurosurgical Department of the Edward Francis Small Teaching Hospital in Banjul, The Gambia. The mission followed the data of neurosurgical operations during and after the mission as well as about the operations 3 months prior to and after the mission was collected. Results: During the mission, a total of 22 operations was carried out, the most common being degenerative spinal conditions (n = 9). In the 3 months following the mission, 43 operations were performed compared to 24 during the 3 months leading up to the mission. The complexity of the performed procedures increased after the mission. An operating microscope (Möller-Wedel) was donated and installed and the neurosurgeons on site underwent training in microneurosurgery. The surgical nurses, nurses at the postoperative ward, and the physiotherapists underwent training. A biomedical engineer serviced multiple appliances and devices improving the patient care on site while training local technicians. Conclusion: This study validated the use of the INTIMA model previously described in a mission by Swedish African Neurosurgical Collaboration (SANC). The model is sustainable and produces notable results. The core strength of the model is in the multidisciplinary team securing all the aspects and steps of the neurosurgical care. Installation of an operating microscope opened for further microsurgical possibilities, improving the neurosurgical care in The Gambia. [ABSTRACT FROM AUTHOR]

In multicomponent systems the diffusion coefficient turns into a matrix. The diagonal elements represent diffusion of a species caused by its own concentration gradient. In a thermodynamically stable binary alloy it is easy to see that this diagonal element must be positive but in a multicomponent system it is less obvious. The sign of the diagonal elements in the general case is discussed in this report. It is shown that the sign of an individual diagonal element has no physical meaning but can be changed by changing the dependent concentration variable. Only the sum of all the diagonal elements need to be positive in a stable system. [ABSTRACT FROM AUTHOR]

In the present paper, a general survey of the diffusion-controlled transformations (DICTRA) software is given. DICTRA is an engineering tool for diffusion simulations in multicomponent alloys. The simulations are based on multicomponent diffusion and thermodynamic data, both obtained by analyzing and assessing experimental information. This allows for many different cases to be studied as soon as the underlying data are available. DICTRA is not a complete simulation tool because only geometries that can be transformed into one space variable can be treated, but many well posed problems of practical interest may be solved. The program contains several different models, which are discussed in the present paper. Each model has its own applications and several examples from recent simulations are given in order to demonstrate the usage of the particular models. [ABSTRACT FROM AUTHOR]

A general model to treat multicomponent diffusion in multiphase dispersions is presented. The model is based on multicomponent diffusion data and basic thermodynamic data and contains no adjustable parameters. No restriction is placed on the number of components or phases that take part in the calculations, as long as the necessary thermodynamic and kinetic data are available. The new model is implemented into the DICTRA software, which makes use of THERMO-CALC to handle the thermodynamics. The model is applied to carburization of Ni alloys and heat treatment of welded joints between dissimilar materials. In both cases, the diffusion is accompanied by carbide formation or dissolution. A good agreement between experiments and calculations is found, despite the fact that no adjustable parameters are needed. [ABSTRACT FROM AUTHOR]