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Search Results: 1 - 10 of 461970 matches for " A. Spinneker "
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Vitamin B6 status, deficiency and its consequences: an overview Estado de vitamina B6, deficiencia y sus consencuencias: una revisión
A. Spinneker,R. Sola,V. Lemmen,M. J. Castillo
Nutrición Hospitalaria , 2007,
Abstract: Background: Vitamin B6 is thought to be a most versatile coenzyme that participates in more than 100 biochemical reactions. It is involved in amino acid and homocysteine metabolism, glucose and lipid metabolism, neurotransmitter production and DNA/RNA synthesis. Vitamin B6 can also be a modulator of gene expression. Nowadays, clinically evident vitamin B6 deficiency is not a common disorder, at least in the general population. Nevertheless, a subclinical, undiagnosed deficiency may be present in some subjects, particularly in the elderly.Objective: This review gives a complete overview over the metabolism and interactions of vitamin B6. Further, we show which complications and deficiency symptoms can occur due to a lack of vitamin B6 and possibilities for public health and supplemental interventions. Methods: The database Medline (www.ncvi.nlm.nih.gov) was searched for terms like "vitamin B6", "pyridoxal", "cancer", "homocysteine", etc. For a complete understanding, we included studies with early findings from the forties as well as recent results from 2006. These studies were summarised and compared in different chapters. Result and conclusion: In fact, it has been proposed that suboptimal vitamin B6 status is associated with certain diseases that particularly afflict the elderly population: impaired cognitive function, Alzheimer's disease, cardiovascular disease, and different types of cancer. Some of these problems may be related to the elevated homocysteine concentrations associated to vitamin B6 deficiency, but there is also evidence for other mechanisms independent of homocysteine by which a suboptimal vitamin B6 status could increase the risk for these chronic diseases. Antecedentes: se piensa que la vitamina B6 es la coenzima más versátil que participa en más de 100 reacciones bioquímicas. Está implicada en el metabolismo de los aminoácidos y de la homocisteína, el metabolismo de la glucosa y los lípidos, en la producción de neurotransmisores y en la síntesis de ADN/ARN. Esta vitamina también puede ser un modulador de la expresión génica. Hoy en día, la deficiencia clínicamente evidente de vitamina B6 no es una afección habitual, al menos en la población general. Sin embargo, puede ocurrir una deficiencia subclínica no diagnosticada en algunos individuos, especialmente en los ancianos. Objetivo: esta revisión aporta una visión de conjunto completa sobre el metabolismo y las interacciones de la vitamina B6. Además, mostramos qué complicaciones y síntomas por deficiencia pueden ocurrir por la falta de vitamina B6 y las posibilidades de intervencion
Vitamin B6 status, deficiency and its consequences: an overview
Spinneker,A.; Sola,R.; Lemmen,V.; Castillo,M. J.; Pietrzik,K.; González-Gross,M.;
Nutrición Hospitalaria , 2007,
Abstract: background: vitamin b6 is thought to be a most versatile coenzyme that participates in more than 100 biochemical reactions. it is involved in amino acid and homocysteine metabolism, glucose and lipid metabolism, neurotransmitter production and dna/rna synthesis. vitamin b6 can also be a modulator of gene expression. nowadays, clinically evident vitamin b6 deficiency is not a common disorder, at least in the general population. nevertheless, a subclinical, undiagnosed deficiency may be present in some subjects, particularly in the elderly.objective: this review gives a complete overview over the metabolism and interactions of vitamin b6. further, we show which complications and deficiency symptoms can occur due to a lack of vitamin b6 and possibilities for public health and supplemental interventions. methods: the database medline (www.ncvi.nlm.nih.gov) was searched for terms like "vitamin b6", "pyridoxal", "cancer", "homocysteine", etc. for a complete understanding, we included studies with early findings from the forties as well as recent results from 2006. these studies were summarised and compared in different chapters. result and conclusion: in fact, it has been proposed that suboptimal vitamin b6 status is associated with certain diseases that particularly afflict the elderly population: impaired cognitive function, alzheimer's disease, cardiovascular disease, and different types of cancer. some of these problems may be related to the elevated homocysteine concentrations associated to vitamin b6 deficiency, but there is also evidence for other mechanisms independent of homocysteine by which a suboptimal vitamin b6 status could increase the risk for these chronic diseases.
M51 revisited: a genetic algorithm approach of its interaction history
Ch. Theis,Ch. Spinneker
Physics , 2003, DOI: 10.1023/A:1024056211087
Abstract: Detailed models of observed interacting galaxies suffer from the extended parameter space. Here, we present results from our code MINGA which couples an evolutionary optimization strategy (a genetic algorithm) with a fast N-body method. MINGA allows for an automatic search of the optimal region(s) in parameter space within a few hours to a few days of CPU time on a modern PC by investigating of the order of 10^5 models. We demonstrate its applicability by modelling the HI intensity and velocity maps of the interacting system M51 and NGC 5195. We get a good fit for the HI intensity map and we can reproduce the counter-rotation feature of the HI arm. Our result corroborates the results of Salo & Laurikainen (2000) who favour a model with multiple passages through M51's disk.
Galaxies and Genes: Towards an Automatic Modeling of Interacting Galaxies
Ch. Theis,Ch. Gerds,Ch. Spinneker
Physics , 2001,
Abstract: The main problems in modeling interacting galaxies are the extended parameter space and the fairly high CPU costs of self-consistent N-body simulations. Therefore, traditional modeling techniques suffer from either extreme CPU demands or trapping in local optima (or both). A very promising alternative approach are evolutionary algorithms which mimic natural adaptation in order to optimize the numerical models. One main advantage is their very weak dependence on starting points which makes them much less prone to trapping in local optima. We present a Genetic Algorithm (GA) coupled with a fast (but not self-consistent) restricted N-body solver. This combination allows us to identify interesting regions of parameter space within only a few CPU hours on a standard PC or a few CPU minutes on a parallel computer. Especially, we demonstrate here the ability of GA-based fitting procedures to analyse observational data automatically, provided the data are sufficiently accurate.
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
Abstract:

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
Abstract:

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
Abstract:

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.

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