Influencia de la marcha en la biomecánica del clavo de Grosse-Kempf

El objetivo de este estudio ha sido conocer la influencia que tiene la deambulación en carga en la posibilidad de rotura del clavo centromedular encerrojado de fémur tipo Grosse- Kempf. El estudio ha consistido en 2 partes: en primer lugar se realiza un estudio estático-lineal del clavo mediante un programa de elementos finitos aplicándole las diferentes fuerzas que el clavo debe de soportar durante la marcha para conocer qué tipo de fuerzas son las que más afectan a su estructura; en segundo lugar hemos llevado a cabo un estudio cinemático-tridimensional de la marcha observando en qué fases de la misma se producen este tipo de fuerzas. Las fuerzas que más afectan al clavo son las de torsión, y el momento en que mayor fuerzas de este tipo se transmiten al clavo durante la marcha es al realizar el apoyo de la extremidad fracturada mientras la extremidad sana se encuentra en el aire. Como conclusión, no debe permitirse la deambulación total en carga en pacientes con el clavo colocado en estático ya que se corre un riesgo innecesario de rotura de material.This study was aimed at knowing the influence of gait with total weight bearing on the possibility of breakage of the Grosse-Kempf's locked femoral nail. The study consisted of two parts: firstly, we carry out a static linear study of the nail by means of a finite element method applying the different forces that the nail support during gait in order to know what type of forces affect more the structure.; secondly a kinematic-tridimensional study of gait was performed showing the phases in which the implant was more affected for different forces. Torsion forces specially at the single lines support phase during gait are the forces inducing the major stress at the implant. As conclusion, total weight bearing showed not be permited in patients with insufficient cortical support or static locking since there is an increase in the risk of breakage of the nail

A decision support system for elective surgery scheduling under uncertain durations

The operation room (OR) is one of the most expensive material resources in hospitals. Additionally, the demand for surgical service is increasing due to the aging population, while the number of surgical interventions performed is stagnated because of budget reasons. In this context, the importance of improving the efficiency of the surgical service is accentuated. The main objective of this work is to propose and to evaluate a Decision Support System (DSS) for helping medical staff in the automatic scheduling of elective patients, improving the efficiency of medical teams'' work. First, the scheduling criteria are fixed and then the scheduling problem of elective patients is approached by a mathematical programming model. A heuristic algorithm is proposed and included in the DSS. Moreover, other different features are implemented in a software tool with a friendly user interface, called CIPLAN. Considering realistic data, a simulation comparison of the scheduling obtained using the approach presented in this paper and other similar approaches in the bibliography is shown and analyzed. On the other hand, a case study considering real data provided by the Orthopedic Surgical Department (OSD) of the "Lozano Blesa" hospital in Zaragoza (HCU) is proposed. The simulation results show that the approach presented here obtains similar occupation rates and similar confidence levels of not exceeding the available time than approaches in the bibliography. However, from the point of view of respecting the order of the patients in the waiting list, the approach in this paper obtains scheduling much more ordered. In the case of the Orthopedic Surgical Department of the "Lozano Blesa" hospital in Zaragoza, the occupation rate may be increased by 2.83%, which represents a saving of 110, 000 euros per year. Moreover, medical doctors (who use this tool) consider CIPLAN as an intuitive, rapid and efficient software solution that can make easier the corresponding task

Rotura distal del tendón de la porción larga del bíceps braquial. ¿por qué está aumentado su incidencia? ¿Cuándo se debe reparar?

Introduction and objectives: The breaking of the distal biceps tendon is rare and represents only 3% of all breakings of this tendon. However, for the last decade this percentage has increased up to 10%. They are characteristic of middle-aged men with a predominance of the dominant arm. Local risk factor (high functional demand) and systemic ones (smoking, dyslipidemia, steroids, analogies, obesity) are associated with this pathology. Our goal is to analyze the risk factors which are associated with this condition and evaluate the results after surgical repair of the tendon. Materials and methods: Retrospective study of 13 patients diagnosed with distal biceps tendon breaking in our hospital from May 2012 to January 2014. All patients were treated surgically with anatomic reattachment single trak (69, 23 % with Endobutton''s technique and 30, 77 % remembering using harpoons). There have been assessed factors such us potential risk factors, joint mobility, early and late complications and the patient''s degree of satisfaction (scale Karunakar). Their clinical follow-up was carried out for at least 6 months after the surgery. Result: All patients were male, with an average age of 42, 69 years, the 92, 3 % were in the dominant arm, 76, 92 % of the patients usually exercised the biceps while training and 53, 84 % were taking medication for dyslipidemia. The results obtained after the treatment were excellent, shawing that all patients were satisfied with it. Conclusion: The risk factors that are known so far such us smoking, dyslipidemia, steroids, anabolics and obesity do not justify the increase in the currents incidence rate. Regular exercise involving the biceps brachial muscle in patients with risk factors increases the probability of breaking the distal biceps tendon and anatomic reattachment anterior approach is a correct treatment option

Quantum Zermelo problem for general energy resource bounds

A solution to the quantum Zermelo problem for control Hamiltonians with general energy resource bounds is provided. Interestingly, the energy resource of the control Hamiltonian and the control time define a pair of conjugate variables that minimize the energy-time uncertainty relation. The resulting control protocol is applied to a single qubit as well as to a two-interacting qubit system represented by a Heisenberg spin dimer. For these low-dimensional systems, it is found that physically realizable control Hamiltonians exist only for certain, quantized, energy resources.Comment: 13 pages, 1 figur

Estudio comparativo clínico y biomecánico de distintos tipos de osteosíntesis en el tratamiento de fracturas distales de fémur

Introducción y objetivos: Las fracturas de fémur distal representan un problema por su elevado número de complicaciones. El objetivo fue comparar los resultados, las complicaciones y la estabilidad conseguidos con el enclavado intramedular retrógrado y la placa de estabilidad angular en el tratamiento de las fracturas diafisarias distales de fémur. Material y método: Se realizó un estudio clínico y experimental biomecánico mediante elementos finitos. Los resultados de las simulaciones permitieron obtener los principales resultados relacionados con la estabilidad de la osteosíntesis. En el seguimiento clínico se utilizaron frecuencias en variables cualitativas, y la prueba exacta de Fisher y la prueba 2para evaluar la significación de los diferentes factores, con la condición p < 0,05. Resultados: En el estudio biomecánico, los clavos intramedulares retrógrados demostraron superioridad, obteniendo valores inferiores en cuanto a desplazamiento global, tensión máxima, resistencia a la torsión y resistencia a la flexión. En el estudio clínico, la tasa de consolidación de las placas fue inferior a la de los clavos (77% vs 96%, p = 0,02). El factor que más influyó en la consolidación de las fracturas tratadas con placa fue el grosor cortical central (p = 0,019). El factor que más influyó en la consolidación de las fracturas tratadas con clavo fue la diferencia entre el diámetro del canal medular y el del clavo. Conclusiones: Nuestro estudio biomecánico demuestra que ambas osteosíntesis proporcionan suficiente estabilidad, pero biomecánicamente se comportan de forma diferente. Los clavos proporcionan mayor estabilidad global, siendo preferible el uso de clavos largos y ajustados al diámetro del canal. Las placas forman osteosíntesis menos rígidas, con poca resistencia a la flexión

Quantum equilibration of the double-proton transfer in a model system porphine

There is a renewed interest in the derivation of statistical mechanics from the dynamics of closed quantum systems. A central part of this program is to understand how closed quantum systems, i.e., in the absence of a thermal bath, initialized far-from-equilibrium can share a dynamics that is typical to the relaxation towards thermal equilibrium. Equilibration dynamics has been traditionally studied with a focus on the so-called quenches of large-scale many-body systems. We consider here the equilibration of a two-dimensional molecular model system describing the double proton transfer reaction in porphine. Using numerical simulations, we show that equilibration indeed takes place very rapidly (∼200 fs) for initial states induced by pump–dump laser pulse control with energies well above the synchronous barrier. The resulting equilibration state is characterized by a strong delocalization of the probability density of the protons that can be explained, mechanistically, as the result of (i) an initial state consisting of a large superposition of vibrational states, and (ii) the presence of a very effective dephasing mechanism

Polyfunctional T cell responses in children in early stages of chronic Trypanosoma cruzi infection contrast with monofunctional responses of long-term infected adults

Background: Adults with chronic Trypanosoma cruzi exhibit a poorly functional T cell compartment, characterized by monofunctional (IFN-γ-only secreting) parasite-specific T cells and increased levels of terminally differentiated T cells. It is possible that persistent infection and/or sustained exposure to parasites antigens may lead to a progressive loss of function of the immune T cells. Methodology/Principal Findings: To test this hypothesis, the quality and magnitude of T. cruzi-specific T cell responses were evaluated in T. cruzi-infected children and compared with long-term T. cruzi-infected adults with no evidence of heart failure. The phenotype of CD4+ T cells was also assessed in T. cruzi-infected children and uninfected controls. Simultaneous secretion of IFN-γ and IL-2 measured by ELISPOT assays in response to T. cruzi antigens was prevalent among T. cruzi-infected children. Flow cytometric analysis of co-expression profiles of CD4+ T cells with the ability to produce IFN-γ, TNF-α, or to express the co-stimulatory molecule CD154 in response to T. cruzi showed polyfunctional T cell responses in most T. cruzi-infected children. Monofunctional T cell responses and an absence of CD4+TNF-α+-secreting T cells were observed in T. cruzi-infected adults. A relatively high degree of activation and differentiation of CD4+ T cells was evident in T. cruzi-infected children. Conclusions/Significance: Our observations are compatible with our initial hypothesis that persistent T. cruzi infection promotes eventual exhaustion of immune system, which might contribute to disease progression in long-term infected subjects.Fil: Albareda, María Cecilia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: de Rissio, Ana María. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Tomas, Gonzalo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Serjan, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Alvarez, María Gabriela. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Viotti, Rodolfo Jorge. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Fichera, Laura Edith. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Potente, Daniel Fernando. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Armenti, Alejandro. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Tarleton, Rick L.. University of Georgia; Estados UnidosFil: Laucella, Susana Adriana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Inflammation affects the viability and plasticity of equine mesenchymal stem cells: Possible implications in intra-articular treatments

Mesenchymal stem cells (MSCs) are gaining relevance for treating equine joint injuries because of their ability to limit inflammation and stimulate regeneration. Because inflammation activates MSC immunoregulatory function, proinflammatory priming could improve MSC efficacy. However, inflammatory molecules present in synovial fluid or added to the culture medium might have deleterious effects on MSCs. Therefore, this study was conducted to investigate the effects of inflammatory synovial fluid and proinflammatory cytokines priming on viability and plasticity of equine MSCs. Equine bone marrow derived MSCs (eBM-MSCs) from three animals were cultured for 72 h in media supplemented with: 20% inflammatory synovial fluid (SF); 50 ng/mL IFN-¿ and TNF-a (CK50); and 20 ng/mL IFN-¿ and TNF-a (CK20). Proliferation assay and expression of proliferation and apoptosis-related genes showed that SF exposed-eBM-MSCs maintained their viability, whereas the viability of CK primed-eBM-MSCs was significantly impaired. Tri-lineage differentiation assay revealed that exposure to inflammatory synovial fluid did not alter eBM-MSCs differentiation potential; however, eBM-MSCs primed with cytokines did not display osteogenic, adipogenic or chondrogenic phenotype. The inflammatory synovial environment is well tolerated by eBM-MSCs, whereas cytokine priming negatively affects the viability and differentiation abilities of eBM-MSCs, which might limit their in vivo efficacy

Many-particle Hamiltonian for open systems with full Coulomb interaction: Application to classical and quantum time-dependent simulations of nanoscale electron devices

Premi a l'excel·lència investigadora. Àmbit de les Ciències Tecnològiques i Enginyeries. 2010A many-particle Hamiltonian for a set of particles with Coulomb interaction inside an open system is described without any perturbative or mean-field approximation. The boundary conditions of the Hamiltonian on the borders of the open system [in the real three-dimensional (3D) space representation] are discussed in detail to include the Coulomb interaction between particles inside and outside of the open system. The many-particle Hamiltonian provides the same electrostatic description obtained from the image-charge method, but it has the fundamental advantage that it can be directly implemented into realistic (classical or quantum) electron device simulators via a 3D Poisson solver. Classically, the solution of this many-particle Hamiltonian is obtained via a coupled system of Newton-type equations with a different electric field for each particle. The quantum-mechanical solution of this many-particle Hamiltonian is achieved using the quantum (Bohm) trajectory algorithm [X. Oriols, Phys. Rev. Lett. 98, 066803 (2007)]. The computational viability of the many-particle algorithms to build powerful nanoscale device simulators is explicitly demonstrated for a (classical) double-gate field-effect transistor and a (quantum) resonant tunneling diode. The numerical results are compared with those computed from time-dependent mean-field algorithms showing important quantitative differences