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Search Results: 1 - 10 of 461896 matches for " A. Marnov "
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Complicaciones de la cirugía craneofacial en tumores de base craneal anterior Complications of craniofacial resection in anterior skull base tumors
A. Torres,J.J. Acebes,L. López,A. Marnov
Neurocirugía , 2005,
Abstract: Introducción. Los recientes avances en radiología, técnica microquirúrgica y de reconstrucción han permitido que la cirugía craneofacial (CCF) se haya convertido en el tratamiento de elección de la patología tumoral de fosa craneal anterior. A pesar de esto, continua asociándose a una incidencia de complicaciones considerable (24-56%). Objetivos. Revisión, análisis y manejo de las complicaciones de la CCF en una serie de 41 pacientes. Material y métodos. 41 pacientes diagnosticados de patología tumoral infiltrativa de base craneal anterior, fueron intervenidos mediante CCF, entre 1990 y 2002. La extensión tumoral fue valorada en todos los casos con TC y RMN de la región craneo-facial. Tras determinar el volumen y extensión tumoral se dise ó un tratamiento quirúrgico radical, con el objetivo de conseguir una resección tumoral "en bloque". Resultados. El 63.4% de los pacientes eran varones con una mediana de edad de 57 a os (18-73). La histología más frecuente de los tumores fue carcinoma escamoso y la localización habitual fue en los senos paranasales en el 78% (32 de 41 casos). En el 85.4% de los pacientes se realizó una craneotomía bifrontal basal y en el 14.6% restante craneotomía frontoorbitaria unilateral, en un sólo colgajo óseo. El área de resección facial incluía: etmoidectomía (60.9%), etmoido-esfenoidectomía (24.3%), maxilectomía unilateral (39%) y exenteración orbitaria (14.6%). Para la reconstrucción se utilizó: colgajo pediculado pericraneal (100%), colgajos locales (34.1%), colgajos libres microvascularizados (21.9%) e injerto óseo autólogo (19.5%). 20 pacientes (48.7%) presentaron complicaciones postoperatorias, entre las que destacan, como complicaciones mayores la fístula de LCR (12.1%) y la meningitis (7.3%). La mortalidad global fue del 7.3%. Conclusiones. La CCF continua asociándose a una elevada tasa de complicaciones, en general de tipo infeccioso. El perfeccionamiento de las técnicas de reconstrucción permitirán reducir la incidencia de las complicaciones más frecuentes y peligrosas. Introduction. The development of new radiographic techniques and the refinement of microsurgery and reconstructive surgery have been the responsible of the establishment of craniofacial resection (CFR) as the standard treatment of anterior skull base tumors. Overall complication rates varies from 24-56%, according to a review of recently published series. Objectives. To describe the complications of CFR in a series of 41 patients and to analyze the management and final outcome. Material and methods. From 1990 to 2002, 41 patients underwent CFR for tumor
Complicaciones de la cirugía craneofacial en tumores de base craneal anterior
Torres,A.; Acebes,J.J.; López,L.; Marnov,A.; Vi?als,J.; Serra,J.M.; Ma?os,M.; Monner,A.;
Neurocirugía , 2005, DOI: 10.4321/S1130-14732005000600003
Abstract: introduction. the development of new radiographic techniques and the refinement of microsurgery and reconstructive surgery have been the responsible of the establishment of craniofacial resection (cfr) as the standard treatment of anterior skull base tumors. overall complication rates varies from 24-56%, according to a review of recently published series. objectives. to describe the complications of cfr in a series of 41 patients and to analyze the management and final outcome. material and methods. from 1990 to 2002, 41 patients underwent cfr for tumors involving the anterior cranial base. the extent of the tumor was always assessed with craniofacial ct-scan and mri. the objective of the surgical treatment was to achive "on block" remo-val of the tumor. results. the average age was 57 years with a male preponderance (63.4%). squamous cell carcinoma was the most frequent histopathological type of tumor. the tumors were localized in paranasal sinuses in 78% of the cases. bifrontal craniotomy was performed in 85.4% and unilateral orbitofrontal craniotomy in 14.6% of the cases. the area of facial resection included: ethmoidectomy (60.9%), ethmoido-sphenoidectomy (24.3%), maxillectomy (39%) and orbital exenteration (14.6%). the reconstruction of the floor of the anterior cranial fossa was performed using pedicled pericranial flap (100%), local (34.1%) or microvascular free flaps (21.9%) and split calvarian graft (19.5%). 20 patients (48.7%) developed post-operative complications, csf leaks (12.1%) and meningitis (7.3%) being the most frequent major complications. the mortality rate was 7.3%. conclusions. cfr has become the standard approach for anterior cranial base tumors. despite its widespread application, the complication's rate ranges between 24-50% and the procedure carries a risk of significant morbidity and even mortality. improvement of specific aspects of surgical technique and more refined reconstructive methods will decrease the number of complications.
The Spread of Infectious Disease on Network Using Neutrosophic Algebraic Structure  [PDF]
A. Zubairu, A. A. Ibrahim
Open Journal of Discrete Mathematics (OJDM) , 2017, DOI: 10.4236/ojdm.2017.72009
Abstract: Network theory and its associated techniques has tremendous impact in various discipline and research, from computer, engineering, architecture, humanities, social science to system biology. However in recent years epidemiology can be said to utilizes these potentials of network theory more than any other discipline. Graph which has been considered as the processor in network theory has a close relationship with epidemiology that dated as far back as early 1900 [1]. This is because the earliest models of infectious disease transfer were in a form of compartment which defines a graph even though adequate knowledge of mathematical computation and mechanistic behavior is scarce. This paper introduces a new type of disease propagation on network utilizing the potentials of neutrosophic algebraic group structures and graph theory.
A Comparative Investigation of Lead Sulfate and Lead Oxide Sulfate Study of Morphology and Thermal Decomposition  [PDF]
S. A. A. Sajadi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22024
Abstract: The compound lead oxide sulfate PbSO4.PbO was prepared in our laboratory. The Thermal behavior of PbSO4 was studied using techniques of Thermogravimetry under air atmosphere from 25 to 1200°C. The identity of both compounds was confirmed by XRD technique. Results obtained using both techniques support same decomposition stages for this compound. The electron microscopic investigations are made by SEM and TEM. The compound is characterized by XRD and the purity was determined by analytical Methods. Also a series of thermogravimetric analysis is made and the ideal condition is determined to convert this compound to pure lead oxide.
Metal ion-binding properties of L-glutamic acid and L-aspartic acid, a comparative investigation  [PDF]
S. A. A. Sajadi
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22013
Abstract: A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
Determining the Basaltic Sequence Using Seismic Reflection and Resistivity Methods  [PDF]
A. Alanezi, A. Qadrouh
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32B004

This study was carried out in Harat Rahat (south of Almadinah Almonwarah) using seismic reflection and resistivity methods. The main objectives of this study are to determine the extent of the basaltic layer and to define the subsurface faults and fractures that could affect and control the groundwater movement in the study area. A 2D seismic profile was acquired and the result shows that the subsurface in the study area has a major fault. We obtained a well match when the seismic result was compared with drilled wells. As a complementary tool, the resistivity method was applied in order to detect the groundwater level. The results of the resistivity method showed that six distinct layers have been identified. The interpretation of these six layers show that the first three layers, the fourth layer, the fifth layer and the bottom of the section indicated various subsurface structures and lithologies; various basaltic layers, fractured basalt, weathered basement and fresh basaltic layers, respectively. It is obvious that the eventual success of geophysical surveys depend on the combination with other subsurface data sources in order to produce accurate maps.

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution  [PDF]
S. A. A. Sajadi
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2014, DOI: 10.4236/ojinm.2014.41001

The acidity and stability constants of M(Gly)1, M(Ttr)1, and M(Trp)1 M: Cu2+, Cu(Bpy2)2+, and Cu(Phen3)2+ complexes, were determined by potentiometric pH titration. It is shown that the stability of the binary Cu(L), (L: Gly, Ttr, and Trp) complex is determined by the basicity of the carboxylate group on one side and amino group on the other side. It is demonstrated that the equilibrium, Cu(Ha4)2+ + Cu(L) \"\"Cu(Har)(L) + Cu2+, is displacement due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a heteroaromatic N base and an O donor ligand possess increased stability. The stability constants of the 1:1 complexes formed between Cu2+, Cu(Bpy)2+ or Cu(Phen)2+

Adaptive Fuzzy Sliding Mode Controller for Grid Interface Ocean Wave Energy Conversion  [PDF]
Adel A. A. Elgammal
Journal of Intelligent Learning Systems and Applications (JILSA) , 2014, DOI: 10.4236/jilsa.2014.62006

This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.

Geochemical Characteristics and Chemical Electron Microprobe U-Pb-Th Dating of Pitchblende Mineralization from Gabal Gattar Younger Granite, North Eastern Desert, Egypt  [PDF]
Hassan A. A. Shahin
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.41003

Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High level emplaced high-K Calc-alkaline plutons as Qattar granite may have been associated with their volcanic equivalent emplaced in the surrounding area or now eroded. Lead content of the pitchblende mineralization is high and with moderate volcanics (up to 7.71% PbO). In contrast, it is low in ThO2, Y2O3 and REE2O3. High Zr and Pb content associated with pitchblende mineralization from Gattar granite indicates

A Comparative Study of Adomain Decompostion Method and He-Laplace Method  [PDF]
Badradeen A. A. Adam
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.521312
Abstract: In this paper, we present a comparative study between the He-Laplace and Adomain decomposition method. The study outlines the significant features of two methods. We use the two methods to solve the nonlinear Ordinary and Partial differential equations. Laplace transformation with the homotopy method is called He-Laplace method. A comparison is made among Adomain decomposition method and He-Laplace. It is shown that, in He-Laplace method, the nonlinear terms of differential equation can be easy handled by the use He’s polynomials and provides better results.
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