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Nanomaterials for Drugs Delivery  [PDF]
Francisco Márquez, Carmen Morant
Soft Nanoscience Letters (SNL) , 2014, DOI: 10.4236/snl.2014.43007
Abstract:

As expected for years, nanotechnology has revolutionized engineering, biology, chemistry, physics and medicine of today. These disciplines are evolving thanks to the ongoing development of new materials and applications. Nanomedicine, as application of nanotechnology in the field of health care, has undergone unprecedented development. Some of these changes have real applications as, for example, the use of nanoparticles in MRI imaging, in hyperthermia, in immunotherapy, or to improve the bioavailability of drugs, among others [1]-[3].

When a drug is administered to a patient, the blood distributes it throughout the body. In the case of very localized diseases (i.e. tumors), only a small fraction of the drug reaches the target. Chemotherapy is one of the most aggressive treatment options used in some types of cancer, and is usually administered intravenously. In this type of therapy, the drug circulates throughout the body, reaching and destroying healthy and cancerous tissues, producing side effects throughout the body, sometimes with serious consequences for the health of the patient (nephrotoxicity, cardiotoxicity, peripheral neuropathy, anemia, etc.). Among the many applications of nanotechnology, the fabrication of nanostructures capable of safely transporting these drugs is seen as a strategy for reducing these side effects. Nanoparticles are able to carry and release the drug in the right place and with the required dose, greatly reducing the problems associated with direct treatment with these drugs.

In recent years, there have been continuous improvements in the design and development of new tailor-made drug delivery systems [4], including hollow magnetic nanoparticles, liposomal structures, dendrimers, nanoporous silicon, etc. These structures can be obtained with different molecular weights (in the case of polymers), structures, shapes, and even with the appropriate functional groups for interaction at the desired positions. However, a great effort is still required to solve many of the current problems [5], including toxicity, aggregation, solubility and stability in the human body, physiological processes of elimination, identification of targets by highly specific receptors, controlled drug release over time, etc.

Nanomaterials for Sensor Applications  [PDF]
Francisco Márquez, Carmen Morant
Soft Nanoscience Letters (SNL) , 2015, DOI: 10.4236/snl.2015.51001
Abstract: Recently, a large part of the advances in nanotechnology have been directed towards the development of high-speed electronics, more efficient catalysts, and sensors. This latter group of applications has great relevance and unprecedented development potential for the coming years.So far, some of the main objectives for the development of sensors have focused on making more sensitive, effective and specific sensing devices.The improvement of these systems and the increase of specificity are clearly associated with a decrease in size of the components, which can lead to obtaining more rapid action, almost in real time. Nanomaterials currently used in sensor development include a long list of nanostructured systems, as for example: metal nanotubes, nanowires, nanofibers, nanocomposites, nanorods, nanoparticles, nanostructured polymers, and different allotropes of carbon as carbon nanotubes, graphene or fullerenes, among others.
Electron Confinement Effect of Laser Dyes within Dendritic Structures  [PDF]
Francisco Márquez, María José Sabater
Journal of Encapsulation and Adsorption Sciences (JEAS) , 2011, DOI: 10.4236/jeas.2011.11001
Abstract: Dendrimers are a novel class of nanometric-size macromolecules with a regular tree-dimensional like array of branch units.1,2 Their synthetic availability in a wide range of sizes combined with their peculiar architecture makes them versatile building blocks for a wide range of potential applications.3 Some years ago, Meijer and co-workers reported that the modification of terminal amine functionalities of a fifth generation poly(propyleneimine) dendrimer (DAB-dendr-(NH2)64) with bulky substituents, (typically N-t-BOC protected phenylalanine), results in the formation of the so-called “dendritic box” (DAB-dendr-(NH-t-BOC-L-Phe)64).4 Within this macromolecular structure it is possible to encapsulate a variety of guest molecules due to the existence of internal cavities in the core. The photophysical properties of the guests can be modulated by the innovative electron confinement effect. In this respect, we wish to report that the emission frequency of organic dyes can be easily modulated by encapsulation in a dendritic box. The emission bands of dye molecules incorporated into a dendrimer can effectively be red shifted with respect to their emission in solution and contrary to other confined spaces of considerable hardness, the magnitude of this shifting can be regulated under appropriate experimental conditions. This peculiar effect could have unprecedented applications in the development of supramolecular devices relating to the frequency tuning of organic laser dyes.
PPAR and Local Renin-Angiotensin Systems in Cardiovascular and Metabolic Diseases Associated with Obesity: A Unifying Hypothesis  [PDF]
Gustavo Márquez-Salom, Javier Diez
Open Journal of Endocrine and Metabolic Diseases (OJEMD) , 2013, DOI: 10.4236/ojemd.2013.35A001
Abstract:

Recent research has revealed roles for the PPAR family of transcription factors in the modulation of the RAAS. In particular, PPARα and PPARγ have been shown to control the transcription of renin in several tissues and influence the activity of local renin-angiotensin-systems coupling vascular and metabolic functions and contributing to their modulation. In this conceptual framework, PPAR and local RAS participate in the pathophysiology of blood pressure elevation, as well as in organ and tissue damage, and disturbances of glucose and lipid metabolism associated with cardiovascular diseases and obesity. The understanding of these mechanisms here discussed and their adequate pharmacological manipulation enlarge the potential to intervene pathological processes that connect the obesity with associate diseases and could alert about the adverse effects of some PPAR agonists on involved organs.

Síntesis electroquímica y propiedades de Polimetoxibencenos
Márquez,Jairo; Márquez,Olga P;
Revista Latinoamericana de Metalurgia y Materiales , 2007,
Abstract: methoxybenzenes are electrochemically oxidized at an electrode surface, in acetonitrile/tetrabutylammonium tetrafluoroborate, with high organic and current yields. in the presence of water, the main reaction product is the alkoxy phenylacetamide, due to a nucleophylic attack of acetonitrile to the aromatic ring, followed by hydrolysis. in anhydrous medium, the main reaction product is a polymer, which is formed following an ece type of mechanism. this polymer forms a bilayer structure on the electrode surface and is insoluble, stable and good conductor of electricity. it is coloured and shows electrochromic properties, and some of them are sensitive to temperature, pressure, light radiation and sound frequency. they can modify electrodes and can be modified by metallic particles. some of these modified materials have been used as electrodes for the reduction process of carbon dioxide and electrolytic oxygen evolution. preparation of these polymers in different media, modified morphology and properties of the material.
Síntesis electroquímica y propiedades de Polimetoxibencenos
Jairo Márquez,Olga P Márquez
Revista Latinoamericana de Metalurgia y Materiales , 2007,
Abstract: Los compuestos metoxi-bencénicos son electrooxidados en acetonitrilo/tetrafluoroborato de tetra n-butilamonio, con altos rendimientos orgánicos y en corriente. Si el medio contiene agua, el producto principal de reacción es la alcoxifenil acetamida, formada por ataque nucleofílico del acetonitrilo al anillo aromático y la posterior hidrólisis. En un medio anhidro, el producto principal de reacción es el polímero, formado mediante un mecanismo catiónico, tipo electroquímico- químico-electroquímico (EQE). Los polímeros forman, generalmente, una bicapa sobre la superficie del electrodo, la cual es estable, insoluble y conductora. Su coloración varía entre compuestos, presentan propiedades electrocrómicas y algunos son sensibles a cambios en la temperatura, presión, irradiación y frecuencia de sonido. Pueden modificar electrodos y ser modificados con partículas metálicas. Algunos electrodos modificados han sido evaluados en procesos de reducción de dióxido de carbono y de inhibición del desprendimiento de oxígeno. La preparación de estos polímeros, en distintos medios electrolíticos, modifica su morfología y propiedades. Methoxybenzenes are electrochemically oxidized at an electrode surface, in acetonitrile/tetrabutylammonium tetrafluoroborate, with high organic and current yields. In the presence of water, the main reaction product is the alkoxy phenylacetamide, due to a nucleophylic attack of acetonitrile to the aromatic ring, followed by hydrolysis. In anhydrous medium, the main reaction product is a polymer, which is formed following an ECE type of mechanism. This polymer forms a bilayer structure on the electrode surface and is insoluble, stable and good conductor of electricity. It is coloured and shows electrochromic properties, and some of them are sensitive to temperature, pressure, light radiation and sound frequency. They can modify electrodes and can be modified by metallic particles. Some of these modified materials have been used as electrodes for the reduction process of carbon dioxide and electrolytic oxygen evolution. Preparation of these polymers in different media, modified morphology and properties of the material.
La estructura de los pensamientos
Márquez Velasco,Leopoldo;
EPISTEME , 2006,
Abstract: in his logical and semantic work gottlob frege holds two apparently contradictory theses about the notion of thought as objective content of judgments and truth bearer: (1) two structurally different sentences can express the same thought; (2) there is an exact correspondence between the elements of a thought and the sentence that expresses it. thus, the structure of the sentence is a model of the structure of the thought. this tension has produced a discussion initiated by michael dummett in the interpretation of frege?s philosophy. in this paper we also discuss the articles by david bell and carlo penco. following the latter, we suggest that the theses are related to two different notions of sense achieving different purposes in the work of the german philosopher.
Imaginarios urbanos en el Gran Santiago: huellas de una metamorfosis
Márquez,Francisca;
EURE (Santiago) , 2007, DOI: 10.4067/S0250-71612007000200007
Abstract: from a reading, between the lines, of the book santiago en eure. huellas de una metamorfosis metropolitana: 1970/2000, this article reflects on the urban imaginaries of santiago presented over the last thirty years. beyond the declared objectives and conceptual frameworks of the authors, it can be noted that aspects of these urban imaginaries filter into and are expressed in each of the selected texts. the analysis focuses on three principal imaginary narratives for the city of santiago: one that persists and resists over time, the imaginary of city/country, and two others that through their incomplete metamorphosis are never resolved by the inhabitants of the city: the imaginary of the integrated city/fractured city and the imaginary of the village city ?world city
El enfoque Frege-Russell: Condiciones de verdad y contenido proposicional
Márquez Velasco,Leopoldo;
EPISTEME , 2009,
Abstract: it is usually stated a ?frege-russell view? in semantics. generally, what is in mind is the ?description theory of proper names?. ?is there, actually, a frege-russell view? in this work, i explore possible differences and similarities among the authors with respect to truth conditions and propositional content. beyond some significant resemblances or divergences, i will show some kind of asymmetry between their views and i will argue for a tension that, at the end, identifies them.
MEMORIA Y APRENDIZAJE EN LA ESCOGENCIA FLORAL DE LAS ABEJAS
AMAYA MáRQUEZ,MARISOL;
Acta Biológica Colombiana , 2009,
Abstract: pollinators highly specialized in their diet do not make food choices by means of cognitive processes; they just follow the dictate writing in their genes. contrary, for the social bee apis mellifera a floral choice implies to make a decision, usually following an economic criterion, based on information acquired from the environment and stored in some form of memory. although there are numerous studies and models about floral choice in bees, most of them have derived their conclusions from 'static' conditions of the interaction. rarely those studies have considered the dynamics of the ecological context, in which seasonality and daily rhythms in floral anthesis change the floral market for the bees. the change in flower species composition faces the pollinators to make sequential choices about what plant species to exploit in each case. in this paper i enter the subject about sequential foraging on heterospecific floral patches, focusing on the use that the bee a. mellifera makes of the information previously learned in a context, when the same bee face food exploitation in a completely different ecological context. i have done some experiments simulating two different floral patches, and exposing individuals of a. mellifera to decide about what floral resource to forage in each patch. the results indicate that the bee initially samples alternatives and they do invest on cognitive process to learn about the best flower species, but once this information is stored in the bee's memory, the bee takes a piece of the learned information (color), to use it as a search image while exploiting heterospecific floral patches. in this paper i discuss biological situations, which support the idea that in nature the use of a color search images by social bees, can be more common than it was thought initially. cost and benefits are derived from this behavior.
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