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Expresión de citoqueratinas y presencia de células ovales. Implicaciones para el estudio del desarrollo del carcinoma hepático

Hugo Mendieta Zerón (2000)

Hepatic carcinoma is one of the most frequently occurring tumors in the Western World with a high mortality rate because it is usually not detected until it is in the advanced clinical stages. The expression of cytokeratins (CK) in the liver, and the presence of oval cells, represents a new investigative field that is focused on the understanding of the development of hepatic neoplasias. The intermediate filaments of cytokeratins are the most numerous structural proteins present in the hepatocytes and in the bile ducts. The study of the oval cells and the expression of cytokeratins offers a new line of study in the development and evolution of the hepatocelular carcinoma.

Article

Multidisciplinarias (Ciencias Sociales) Hepatic carcinoma Cytokeratins Oval cells Hepatocelular carcinoma Hepatocytes BIOLOGÍA Y QUÍMICA

Galacto-Oligosaccharides and Lactulose as Protectants Against Desiccation of Lactobacillus delbrueckii subsp. bulcaricus

Edgar León Esparza Ibarra (2014)

Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 was dehydrated on desiccators

containing silica gel in the presence of 20% w/w of two types of galactooligosaccharides

(GOS Biotempo and GOS Cup Oligo H-70VR ) and lactulose, until no

changes in water desorption were detected. After rehydration, bacterial growth was monitored

at 37 C by determining: (a) the absorbance at 600 nm and (b) the near infrared

spectra (NIR). Principal component analysis (PCA) was then performed on the NIR spectra

of samples dehydrated in all conditions. A multiparametric flow cytometry assay was

carried out using carboxyfluorescein diacetate and propidium iodide probes to determine

the relative composition of damaged, viable, and dead bacteria throughout the growth

kinetics. The absorbance at 600 nm and the position of the second derivative band at

1370 nm were plotted against the time of incubation. The efficiency of the protectants

was GOS Biotempo>GOS Cup Oligo H-70VR >lactulose. The better protectant capacity

of GOS Biotempo was explained on the basis of the lower contribution of damaged cells

immediately after rehydration (t50). PCA showed three groups along PC1, corresponding

to the lag, exponential and stationary phases of growth, which explained 99% of the

total variance. Along PC2, two groups were observed, corresponding to damaged or viable

cells. The results obtained support the use of NIR to monitor the recovery of desiccated

microorganisms in real time and without the need of chemical reagents. The use

of GOS and lactulose as protectants in dehydration/rehydration processes was also supported.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ

Article

BIOLOGÍA Y QUÍMICA Lactobacillus delbrueckii subsp bulgaricus desiccation galacto-oligosaccharides lactulose near infrared spectroscopy multiparametric flow cytometry damage cells

Galacto-Oligosaccharides and Lactulose as Protectants Against Desiccation of Lactobacillus delbrueckii subsp. bulcaricus

EDGAR LEON ESPARZA IBARRA (2014)

Lactobacillus delbrueckii subsp. bulgaricus CIDCA 333 was dehydrated on desiccators

containing silica gel in the presence of 20% w/w of two types of galactooligosaccharides

(GOS Biotempo and GOS Cup Oligo H-70VR ) and lactulose, until no

changes in water desorption were detected. After rehydration, bacterial growth was monitored

at 37 C by determining: (a) the absorbance at 600 nm and (b) the near infrared

spectra (NIR). Principal component analysis (PCA) was then performed on the NIR spectra

of samples dehydrated in all conditions. A multiparametric flow cytometry assay was

carried out using carboxyfluorescein diacetate and propidium iodide probes to determine

the relative composition of damaged, viable, and dead bacteria throughout the growth

kinetics. The absorbance at 600 nm and the position of the second derivative band at

1370 nm were plotted against the time of incubation. The efficiency of the protectants

was GOS Biotempo>GOS Cup Oligo H-70VR >lactulose. The better protectant capacity

of GOS Biotempo was explained on the basis of the lower contribution of damaged cells

immediately after rehydration (t50). PCA showed three groups along PC1, corresponding

to the lag, exponential and stationary phases of growth, which explained 99% of the

total variance. Along PC2, two groups were observed, corresponding to damaged or viable

cells. The results obtained support the use of NIR to monitor the recovery of desiccated

microorganisms in real time and without the need of chemical reagents. The use

of GOS and lactulose as protectants in dehydration/rehydration processes was also supported.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ

Article

BIOLOGÍA Y QUÍMICA Lactobacillus delbrueckii subsp bulgaricus desiccation galacto-oligosaccharides lactulose near infrared spectroscopy multiparametric flow cytometry damage cells

Diseño y análisis de celdas de memoria en presencia de radiación

JESUS MORENO MORENO (2007)

La interacción de un sistema espacial con su ambiente es una consideración importante en el diseño de cualquier sistema espacial, ya que existen una gran variedad de peligros que se asocian a la operación de un sistema en el ambiente hostil del espacio. El ambiente espacial tiene una estructura compleja y dinámica. Existe una gran cantidad de procesos físicos como: partículas cargadas, plasmas, campos eléctricos y magnéticos, radiación solar, meteoros, etc. cada uno pueden causar daños profundos a un sistema espacial, deteriorando su funcionamiento y reduciendo su tiempo de vida. Las interacciones entre un sistema espacial y su ambiente pueden causar modificaciones al ambiente natural, dando lugar a los ambientes locales que alternadamente afectan el comportamiento del sistema [1].

Las numerosas anomalías operacionales y las fallas en sistemas espaciales se han reportado desde los principios de la edad espacial, un número significativo de las cuales fueron atribuidos a los efectos de la radiación en sistemas electrónicos. Las teorías del daño de la radiación en materiales semiconductores se presentaron en los años de los 50's, pues era una necesidad urgente entender por que los dispositivos semiconductores usados en el espacio y el equipo militar presentaban un mal funcionamiento después de la exposición al ambiente del espacio o a las explosiones nucleares. Un caso particular de la radiación fue postulada por primera vez por Wallmark y Marcus en 1962 [2]. Ésta era la posibilidad de "sus esos aislados" o "single events effects" (SEE), donde una sola partícula cargada de energía causa una alteración en el estado lógico en un nodo sensible del dispositivo. Las primeras anomalías en los satélites reales fueron divulgadas por Binder et al. en 1975 [3].

Existen dos tipos de mecanismos físicos producidos por la radiación que pueden afectar a los materiales de los dispositivos electrónicos: ionizantes, el daño se debe principalmente a la liberación de carga, y no ionizantes o por desplazamiento, el daño se produce al ser arrancados átomos de la red cristalina. Ambos mecanismos no son excluyentes y pueden

suceder de forma simultánea. Por ejemplo, un protón puede chocar con los átomos de un material creando defectos cristalinos y, al mismo tiempo, crear un exceso de carga libre al arrancar electrones a lo largo de su trayectoria.

Master thesis

Radiation Cells (Electric) Hardening CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA DISPOSITIVOS SEMICONDUCTORES

Desarrollo de celdas solares de heterounión c-Si / a-Si:H

JOSE DE JESUS MARTINEZ BASILIO (2011)

This work is focused on the design, manufacture and characterization of pin and nip heterojunction solar cells. These solar cells were made on crystalline silicon with depositions of intrinsic and doped hydrogenated amorphous silicon thin films, at low temperatures (< 200 ºC) by means of the Plasma Enhanced Chemical Vapor Deposition (PECVD) Technique.

Nip solar cells were made on p-type crystalline silicon with an intrinsic buffer layer and n-type hydrogenated amorphous silicon thin film. A layer of Oxide Tin Film was deposited as a transparent conductive oxide (TCO). The metal contacts were formed by aluminum evaporation. Pin solar cells were made on n-type crystalline silicon with an intrinsic buffer layer and p-type hydrogenated amorphous silicon thin film. The characterization was carried out by obtaining the current - voltage curves under illumination using a lamp with a known irradiance. In this way, the short circuit current density (Jsc), the open circuit voltage (Voc) and efficiency were obtained.

Also, an analysis about the effect of varying the flow rates of phosphine and diborane in the deposition of the amorphous films (n and p type, respectively) was performed, aiming to study their influence in the characteristics of the performance of the solar cells. It has found that the best efficiency was achieved with the deposition of an a-Si:H thin film doped with diborane with flow of 10 sccm. It was found that the main limiting factor in the efficiency of the cells was a high resistance due to the non ohmic metal-semiconductor contacts. Several techniques were used to reduce the series resistance in the cells and therefore increase the fill factor and the efficiency. However, that was not achieved in a satisfactory way.

Moreover, a simulation study was performed in the cells, varying the resistance value of the back metal-semiconductor contact. It was found that a resistance value of above 10 - 20 Ωcm2 results in a fill factor very small and consequently in a very low efficiency of the solar cells. Finally, we can conclude that the developed process in the present thesis, has the potential to fabricate cells with better characteristics and larger efficiencies, once that the large series resistance has been reduced.

En el presente trabajo se realizó la fabricación y caracterización de celdas solares de hetero unión nip y pin. Las cuales fueron fabricadas sobre sustratos de silicio cristalino, donde posteriormente se depositaron películas delgadas de silicio amorfo intrínseco y silicio amorfo dopado, a bajas temperaturas (≤ 200ºC) por medio de la técnica de Depósito Químico en Fase Vapor Asistido por Plasma (PECVD).

Para la fabricación de celdas nip se utilizaron sustratos de silicio cristalino tipo p, sobre el cual se depositó una película delgada de a-Si:H intrínseco y, posteriormente, una película delgada de silicio amorfo hidrogenado dopado con fósforo, es decir a-Si:H tipo n, como capa anti reflejante se utilizó una película de Óxido de Indio Estaño ITO (Indium Tin Oxide) y finalmente, los contactos metálicos se realizaron por medio de evaporación de aluminio. Las celdas pin se fabricaron sobre silicio cristalino tipo n, sobre el cual se depositaron películas delgadas de silicio amorfo intrínseco y silicio amorfo dopado con boro, es decir a-Si:H tipo p . La caracterización se llevó a cabo por medio de la obtención de curvas corriente voltaje bajo iluminación, usando una lámpara de irradiancia conocida. De esta manera se extrajeron los parámetros de la densidad de corriente de corto circuito (Jsc), el voltaje de circuito abierto (Voc) y la eficiencia del dispositivo.

También se realizó un análisis sobre el efecto al variar los flujos de los gases dopantes en las películas amorfas (tipo n y p, respectivamente), con el objetivo de estudiar su influencia en las características de desempeño de las celdas fabricadas. Los resultados obtenidos muestran que el mejor desempeño de la celda se obtuvo al depositar una película de a-Si:H dopado

con boro con un flujo de 10 sccm, logrando obtener una eficiencia del 5.8%. Se encontró que la principal limitante de la eficiencia de las celdas solares fabricadas fue una alta resistencia en serie debido a los contactos no óhmicos metal-semiconductor y/o al efecto de tener una película intrínseca de un grosor mayor a 5 nm. Se utilizaron distintas técnicas para reducir la resistencia en serie en las celdas y de esta manera lograr un mayor factor de llenado y una mayor eficiencia. Sin embargo no fue posible reducirla.

Para confirmar que la resistencia en serie estaba limitando el funcionamiento de las celdas solares, se realizaron diversas simulaciones.

Master thesis

Solar cells Pn junctions Design CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Study of optoelectronic characteristics in Germanium- Silicon films deposited by low frequency plasma and related devices

FRANCISCO TEMOLTZI AVILA (2014)

The thin film photovoltaic devices are considered as a promising alternative to conventional crystalline silicon solar cells because: 1) less material is needed per unit area to fully absorb the visible part of the solar spectrum (i.e., the thin film solar cells need intrinsic films with thickness of around ≈0.3𝜇𝑚 to fully absorb the visible part of the solar spectrum, whereas the dominant crystalline and polycrystalline silicon solar cells need intrinsic films with thickness of around ≈300𝜇𝑚), 2) can be fabricated photovoltaic modules of very large area in comparison with crystalline and polycrystalline silicon photovoltaic modules, 3) can be perform fabrication processes at low temperature using a wide variety of substrates (flexible, rigid, metals or insulators), films (contacts, buffers, active films, reflectors, etc.) and semiconductor materials (silicon, germanium, cadmium telluride, etc.) deposited by a variety of deposition techniques (PVD, CVD, ECD, plasma-based, hybrid, etc.), and 4) manufacturing and installation costs are significantly lower. Consequently, a wide variety of these technologies are being developed and marketed, including amorphous silicon, polymorphous silicon, microcrystalline silicon, polycrystalline silicon, silicon-germanium alloys, cadmium-telluride alloys, copper-indium-gallium-selenium alloys, organic materials, etc. These developments have made it necessary a better understand of the physics of the thin film solar cell devices. However, at present there are still many important issues that have not been studied enough.

Doctoral thesis

Photovoltaic cells Amorphous semiconductors Characteristics measurement CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA

Directing the self-assembly of tumour spheroids by bioprinting cellular heterogeneous models within alginate/gelatin hydrogels

Tao Jiang JOSE GIL MUNGUIA LOPEZ SALVADOR FLORES TORRES ANTONIO DE LEON RODRIGUEZ Joseph Kinsella (2017)

"Human tumour progression is a dynamic process involving diverse biological and biochemical events such as genetic mutation and selection in addition to physical, chemical, and mechanical events occurring between cells and the tumour microenvironment. Using 3D bioprinting we have developed a method to embed MDA-MB-231 triple negative breast cancer cells, and IMR-90 fibroblast cells, within a cross-linked alginate/gelatin matrix at specific initial locations relative to each other. After 7 days of co-culture the MDA-MB-231 cells begin to form multicellular tumour spheroids (MCTS) that increase in size and frequency over time. After similar to 15 days the IMR-90 stromal fibroblast cells migrate through a non-cellularized region of the hydrogel matrix and infiltrate the MDA-MB-231 spheroids creating mixed MDA-MB-231/IMR-90 MCTS. This study provides a proof-of-concept that biomimetic in vitro tissue coculture models bioprinted with both breast cancer cells and fibroblasts will result in MCTS that can be maintained for durations of several weeks."

Article

Biomaterials – cells Biomedical engineering Cancer models Tissue engineering INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS CIENCIAS TECNOLÓGICAS

Study of inverted planar CH3NH3PbI3 perovskite solar cells fabricated under environmental conditions

JESUS MANUEL RIVAS MARTINEZ (2019)

Organic-inorganic inverted perovskite solar cells have been analyzed. This structure uses organic semiconductors as electron and hole selective electrodes and the perovskite as light harvesting layer. The anti-solvent deposition method is a frequently used techniques in the elaboration of conventional perovskite solar cells (FTO/TiO2/ CH3NH3PbI3/Spiro-OMetad/Au). However, the anti-solvent method is seldom used in the inverted structure. In this work, we use the anti-solvent method to fabricate the perovskite film for solar cells in the ITO/PEDOT:PSS/ CH3NH3PbI3/PC61BM/Ag configuration, systematically studying the effect of the anti-solvent dripping time and the relative humidity in cell fabrication and performance. The morphological, optical and photovoltaic analyses indicate that the right combination of these two parameters will result in a preferential crystal growth in the (1 1 0) orientation. This allows the formation of homogeneous pinhole-free films that enhance light harvesting and reduce charge-carrier leakage, hence increasing short circuit current and fill factor to obtain a photo-con- version efficiency of about ∼10%.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ

Article

INGENIERÍA Y TECNOLOGÍA Inverted structure Perovskite Solar cells

Synchronization and activation in a model of a network of β-cells

JUAN GONZALO BARAJAS RAMIREZ Alejandro Ricardo Femat Flores Henk Nijmeijer (2011)

"Islets of pancreatic β-cells are of utmost importance in the understanding of diabetes mellitus. We consider here a model of a network of such pancreatic β-cells which are globally coupled via gap junctions. Some of the cells in the islet produce bursting oscillations while other cells are inactive. We prove that the cells in the islet synchronize if the coupling is sufficiently large and all cells are active (or inactive). If the islet consists of both active and inactive cells and the coupling is sufficiently large, an active cluster and an inactive cluster emerge. We show that activity of the islet depends on the coupling strength and the number of active cells compared to the number of inactive cells. If too few cells are active the islet becomes inactive."

Article

Network synchronization β Cells Activation Coupling CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA MATEMÁTICAS MATEMÁTICAS

Physiology and Pathology of Innate Immune Response Against Pathogens

MARIA ALEJANDRA MORENO GARCIA (2017)

Pathogen infections are recognized by the immune system, which consists of two types

of responses: an innate immune response and an antigen-specific adaptive immune

response. The innate response is characterized by being the first line of defense that occurs

rapidly in which leukocytes such as neutrophils, monocytes, macrophages, eosinophils,

mast cells, dendritic cells, etc., are involved. These cells recognize the pathogen-associated

molecular patterns (PAMPs), which have been evolutionarily conserved by the diversity

of microorganisms that infect humans. Recognition of these pathogen-associated molecular

patterns occurs through pattern recognition receptors such as Toll-like receptors and

some other intracellular receptors such as nucleotide oligomerization domain (NOD),

with the aim of amplifying the inflammation and activating the adaptive cellular immune

response, through the antigenic presentation. In the present chapter, we will review the

importance of the main components involved in the innate immune response, such as different

cell types, inflammatory response, soluble immune mediators and effector mechanisms

exerted by the immune response against bacteria, viruses, fungi, and parasites; all

with the purpose of eliminating them and eradicating the infection of the host.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ

Book part

BIOLOGÍA Y QUÍMICA innate immune response eosinophils mast cells cytokines inflammatory response bacteria fungi viruses parasites