Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Medicine (Baltimore) ; 99(43): e22807, 2020 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-33120801

RESUMEN

We aimed to establish and validate a nomogram for predicting the disease-specific survival of invasive lobular carcinoma (ILC) patients.The Surveillance, Epidemiology, and End Results program database was used to identify ILC from 2010 to 2015, in which the data was extracted from 18 registries in the US. Multivariate Cox regression analysis was performed to identify independent prognostic factors and a nomogram was constructed to predict the 3-year and 5-year survival rates of ILC patients based on Cox regression. Predictive values were compared between the new model and the American Joint Committee on Cancer staging system using the concordance index, calibration plots, integrated discrimination improvement, net reclassification improvement, and decision-curve analyses.In total, 4155 patients were identified. After multivariate Cox regression analysis, nomogram was established based on a new model containing the predictive variables of age, the primary tumor site, histology grade, American Joint Committee on Cancer TNM (tumor node metastasis) stages II, III, and IV, breast cancer subtype, therapy modality (surgery and chemotherapy). The concordance index for the training and validation cohorts were higher for the new model (0.781 and 0.832, respectively) than for the old model (0.733 and 0.779). The new model had good performance in the calibration plots. Net reclassification improvement and integrated discrimination improvement were also improved. Finally, decision-curve analyses demonstrated that the nomogram was clinically useful.We have developed a reliable nomogram for determining the prognosis and treatment outcomes of ILC. The new model facilitates the choosing of superior medical examinations and the optimizing of therapeutic regimens with cooperation among oncologists.


Asunto(s)
Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Carcinoma Lobular/mortalidad , Carcinoma Lobular/patología , Nomogramas , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Persona de Mediana Edad , Clasificación del Tumor , Invasividad Neoplásica , Estadificación de Neoplasias , Pronóstico , Análisis de Regresión , Reproducibilidad de los Resultados , Factores Sexuales , Factores Socioeconómicos , Análisis de Supervivencia
2.
Biotechnol Prog ; 31(1): 25-34, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25311613

RESUMEN

Lignocellulosic biomass is the most abundant naturally renewable organic resource for biofuel production. Because of its recalcitrance to enzymatic degradation, pretreatment is a crucial step before hydrolysis of the feedstock. A variety of pretreatment methods have been developed and intensively studied to achieve optimal yield without imposing significant adverse impact on the environment. Herein, we present a novel chemical pretreatment method using substituted heterocycles with low temperature and short residence time requirements. 1-Methylimidazole (MI) is a precursor to some imidazolium-based ionic liquids. In this study, its potential utilization as a biomass pretreatment agent is being investigated for the first time. At mild conditions, such as 25°C for 5 min at ambient pressure, a substantial increase in the hydrolysis rate throughout the entire course of conversion for cellulose substrate was obtained. Furthermore, the pretreatment effectiveness of MI on both untreated and steam-exploded lignocellulosic biomass including loblolly pine, switchgrass, and sugarcane bagasse has been studied and MI was found to be an efficient delignifier. Remarkable rate enhancement was also observed for the non-woody lignocellulosic substrates after a short period of MI pretreatment at ambient conditions. The mechanism of MI pretreatment is explored through analysis of cellulose physical properties including crystallinity index, degree of polymerization, accessibility, and lignin dissolution quantification.


Asunto(s)
Biomasa , Biotecnología/métodos , Imidazoles/química , Lignina/química , Biocombustibles , Hidrólisis , Pinus taeda/química , Saccharum/química
3.
Curr Opin Biotechnol ; 29: 139-45, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24794535

RESUMEN

This review covers the topic of protein engineering of cellulases, mostly after 2009. Two major trends that are identified in this work are: first, the increased importance of results from computational protein engineering to drive ideas in the field, as experimental ideas and results often are still scarce, and, second, the further development of helper proteins for cellulose hydrolysis, such as lytic polysaccharide monooxygenase (LPO). The discussion in this work focuses both on improved attributes of cellulases and on the domains of cellulase that have been improved.


Asunto(s)
Celulasas/metabolismo , Ingeniería de Proteínas/métodos , Biocatálisis , Celulosa/metabolismo , Estabilidad de Enzimas , Glicosilación
4.
Biotechnol Prog ; 29(4): 909-16, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23749425

RESUMEN

Lignocellulosic biomass is the most promising feedstock for biofuels production. To enhance the efficiency of enzymatic hydrolysis, lignocellulosics needs to be pretreated to lower their recalcitrance. SO(2) -catalyzed steam explosion is an efficient and relatively cost-efficient pretreatment method for softwood. This work investigates the effects of steam explosion severity on the digestibility, accessibility, and crystallinity of Loblolly pine. Higher severity was found to increase the accessibility of the feedstock while also promoting nonselective degradation of carbohydrates. The adsorption behavior of Celluclast® enzymes on steam-exploded Loblolly pine (SELP) can be described by a Langmuir isotherm. Cellulose crystallinity was found to first increase and then decrease with increasing pretreatment severity. A linear relationship between initial hydrolysis rates and crystallinity index (CrI) of pretreated Loblolly pine was found; moreover, a strong correlation between X-ray diffraction intensities and initial rates was confirmed. The findings demonstrate the significance of CrI in enzymatic hydrolysis of pretreated lignocellulosic biomass.


Asunto(s)
Biomasa , Lignina/metabolismo , Pinus taeda/metabolismo , Prunus/enzimología , Dióxido de Azufre/química , beta-Glucosidasa/metabolismo , Adsorción , Catálisis , Celulasa/metabolismo , Cristalización , Hidrólisis , Lignina/química , Ácidos Fosfóricos/química , Pinus taeda/química , Propiedades de Superficie , Trichoderma/enzimología , Difracción de Rayos X
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...