2,213 research outputs found
Criterio gráfico para la determinación de la existencia de biestabilidad óptica en interfases no lineales
Basándose en la propuesta de Kaplan sobre la posibilidad de obtener conmutación biestable entre un campo homogéneo y otro inhomogéneo transmitidos a un semiespacio no lineal cuando una onda plana incide desde un semiespacio lineal, los autores desarrolla un método gráfico similar al que se utiliza en el estudio de BO en resonadores no lineales
New non-reorientational, non-thermal optical nonlinear effect in MBBA
It is widely known the anular-shaped beam divergence produced by the optical reorientation induced in nematics by a Gaussian beam. Recent works have found a new effect in colored liquid crystal (MBBA, Phase V,...) showing a similar spatial distribution. A new set of random-oscillating rings appears for light intensities over a certain threshold. The beam divergence due to that effect is greater than the molecular reorientation induced one
Estudio experimental del comportamiento no lineal de una interfase entre vidrio y MBBA nemático y análisis de la factibilidad de commutación biestable en interfases no lineales negativas
Se realiza un estudio experimental del comportamiento de una interfase entre un mnedio lineal y otro no lineal, basándose en la propuesta de Kaplan de Biestables Ópticos
Diagnosticand pronostic utility of serum microrna-21 in colorectal cancer
Los microRNAs son estructuras moleculares de 20-22 nucleótidos con actividad post-transcripional que están
implicados en la carcinogénesis mediante una regulación genética post-transcripcional. Presentamos un estudio prospectivo
donde se determina la expresión sérica de microRNA-21 en pacientes con diagnóstico de adenocarcinoma de colon.
MATERIAL Y MÉTODOS. Estudio de cohorte prospectivo de al menos 100 pacientes con diagnóstico de adenocarcinoma de colon,
y de al menos 60 pacientes con apendicitis aguda como grupo control. Se realizó el análisis de microRNA-21 sérico mediante
PCR de las muestras sanguíneas de los pacientes obtenidas de forma preoperatoria.
RESULTADOS. La comparación de la expresión del microRNA-21 sérico fue mayor en los pacientes con cáncer colorrectal que
en los pacientes del grupo control, siendo el área bajo la curva de 0,603. En el análisis univariante, la expresión del miR-
21 se relaciona de forma estadísticamente significativa con la recidiva local (p=0,025) y con la mortalidad (p=0,029). En el
análisis multivariante también se puso de manifiesto que las expresiones mayores (sobreexpresiones) de miR-21 se relacionaban
con una reducción del riesgo derecidiva del 51%, mientras que dicha sobreexpresión se relacionaba con una reducción
de mortalidad del 50%.
CONCLUSIONES. La expresión del microRNA-21 sérico podría ser considerado como un potencial marcador diagnóstico para
el cáncer colorrectal. La expresión sérica del microRNA-21 se correlaciona con la recidiva y mortalidad en el cáncer colorrectal.
Nuestros resultados sugieren que el miR-21 sérico es un prometedor marcador diagnóstico y pronóstico, y pone de
manifiesto su potencial utilidad clínica en el cáncer colorrectalMicroRNAs (miRNAs) are small, noncoding RNAs that are involved in carcinogenesis through postranscriptional
gene regulatory activity. Few studies have focused on the detection of miR-21 in serum rather than in tissue. The current
study aimed to measure serum miR-21 expression levels and to evaluate their association with the outcome of colorectal cancer
(CRC).
METHODS. Blood samples were collected from almost 100 CRC patients undergoing surgery with curative intent, and almost
60 control patients. The expression levels of miR-21 were measured using a quantitative reverse transcription polymerase
chain reaction (qRT-PCR).
RESULTS. Serum microRNA-21 expression was higher in colorectal cancer patients than in control patients, with a ROC curve
of 0.603. A univariate analysis revealed that lower expression levels of serum miR-21 were associated with higher local recurrence
(p=0.025) and mortality (p=0.029). A logistic regression analysis demonstrated that the relative overexpression of
miR-21 (expression >1) was associated with a 51% reduction in the risk of recurrence. A Cox regression analysis identified
that a relative increase in miR-21 expression (>1) was associated with a 50% reduction in the risk of mortality
CONCLUSIONS. Serum microRNA-21 expression could be considered as a potential diagnostic marker for colorectal cancer. The
expression level of serum miR-21 correlates with the recurrence and mortality of CRC patients. Our results suggest that circulating
serum miR-21 is a promising diagnostic and prognostic tumour marker, and they highlight the potential clinical utility
of miR-21 in colorectal cancerEl presente estudio ha sido financiado con la ayuda otorgada por la
Fundación para la Investigación Sanitaria en Castilla La Mancha (FISCAM)
y por la Fundación Mutua Madrileña Investigación Médic
Optical nonlinearities and blstability in a glass-liquid crystal interface
As reported previously, an interface between linear and liquid crystal media shows some nonlinear properties that can be employed in the analysis of this type of optical bistable device
New non-reorientational optical nonlinear effect in MBBA
A new effect producing self-focusing of light in a nematic MBBA film is reported. This effect produces a static diffraction pattern composed of circular rings which is
different from the ones arising from self-focusing previously reported. The influence of the cell thickness, the optical intensity, and the wavelength is studied. Once the nematic is distorted by a láser beam, the effect produced in other light beam passing through the modified región is independent of its polarization. This isotropic behavior shows that a molecular reorientation has not been produced. The origin of this effect seems to be the same of that of the effect which produces a randomly oscillating
diffraction pattern previously reported by our group. Some possible causes such as thermal indexing, convective instabilities and self-induced transparency are discussed
Colorectal cancer carcinogenesis
El cáncer colorrectal representó en el año 2008 el tercer tumor más diagnosticado en España, siendo la segunda neoplasia
que causó más fallecimientos. El conocimiento del proceso carcinogenético de este tipo de enfermedad permitirá el descubrimiento
de nuevas terapéuticas que conlleven menores tasas de incidencia y mortalidad. El continuo avance en la enfermedad
tumoral hace que esta revisión sea una puesta al día en el conocimiento de la carcinogénesis del cáncer colorrectalIn 2008, colorectal cancer represented the third most commonly diagnosed tumor in Spain, and the second tumor that caused
more deaths. Knowledge of the carcinogenetic process of this disease will allow the discovery of new therapies involving
lower rates of incidence and mortality. The continuous progress in tumor disease makes this review an update on the knowledge
of colorectal cancer carcinogenesi
Morphological integration of mandible and cranium: Orthodontic implications
Objectives: This study aimed at clarifying the morphological interactions among the cranial base, face, and mandible, to improve the assessment and treatment of skeletal malocclusions involving the mandible. Design Untreated adult subjects (n = 187) were grouped according to standard cephalometric criteria of vertical and sagittal relationships. Geometric morphometrics were used to test the null hypothesis that integration patterns between the mandible and its associated basicranial and upper midfacial counterparts would be similar among various vertical and sagittal facial patterns. Results: The null hypothesis was rejected for vertical groups, because the dolicho- and brachyfacial subjects showed significantly different integration patterns, but was accepted for sagittal groups, which showed identical covariation patterns. The morphological integration between the cranium-face and mandible were similarly high in the three skeletal classes, which explained the similarly large covariance between the two structures (57.80% in Class II to 60% in Class III). Conclusions: Dolicho- and brachi-facial subjects showed specific and different cranium-face and associated mandible configurations. The cranium-face configuration may have an important influence (∼60%) on the generation of sagittal (anteroposterior) skeletal malocclusions. The remaining morphological component of the skeletal malocclusion (∼40%) would be independent of this particular integration (PLS1) between the cranium-face and mandible. © 2013 Elsevier Ltd.This research was founded by the Spanish Ministry of Economy and Competitiveness (Projects CGL2012-36682 and CGL2012-37279).Peer Reviewe
Microrna-21 and colorectal cancer
Introducción. Los microRNAs son estructuras moleculares con actividad post-transcripcional que están implicados en la
regulación de la expresión genética. Diversos estudios ponen de manifiesto la participación de los microRNAs con distintas
funciones fisiológicas, así como con el proceso de la oncogénesis. La expresión de los microRNAs puede verse alterada en las
neoplasias por su interacción bien con los genes supresores de tumores, bien con los oncogenes.
Discusión. Llevamos a cabo una revisión de la literatura sobre el microRNA-21, poniendo de manifiesto la evidencia existente
entre el microRNA-21 y la enfermedad neoplásica, de forma especial con el cáncer colorrectal.
Conclusiones. El estado actual de los microRNAs hace necesario continuar con la investigación existente entre la etiopatogenia
de las neoplasias y los microRNAs. El conocimiento de la verdadera implicación de los microRNAs en la fisiopatología
de la enfermedad neoplásica, permitirá ampliar las supuestas aplicaciones clínicas del miR-21 no sólo a la determinación
del pronóstico del cáncer colorrectal, sino también desde el punto de vista diagnóstico al poder diferenciar las lesiones de la
mucosa colónicaIntroduction. MicroRNAs are molecular structures with post-transcriptional activity, involved in the gene expression regulation.
Several studies have demonstrated the involvement of microRNAs in different physiological functions, as well as in the
oncogenesis process. The expression of microRNAs may be altered in the tumors by either interaction with tumor suppressor
genes or oncogenes.
Discussion. A review of the medical literature on microRNA-21 has been conducted, showing the evidence between
microRNA-21 and neoplastic disease, specially with colorectal cancer.
Conclusion. The current status of microRNAs makes necessary to continue the investigation of the pathogenesis of cancer and
microRNAs. The knowledge of the involvement of microRNAs in the pathophysiology of neoplastic disease, will allow to extend
the supposed clinical applications of miR-21 not only to the determination of the prognosis of colorectal cancer, but also for
the differential diagnosis of processes of colonic mucosa
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