Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
Materials (Basel) ; 15(23)2022 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-36500122

RESUMEN

In this study, the production of a mortar was proposed in which plastic waste replaced sand by 0%, 50%, and 100% in order to create a sustainable alternative for construction. The performance of the mortars was tested with two types of activators, one with NaOH, as a simple activator, and the other with NaOH and Na2SiO3, as a compound activator. The effects of the LDPE plastic bag waste and the activators on compressive strength, porosity, microstructure analysis, and efflorescence formation were correlated and discussed. The results showed that the replacement of sand with plastic waste at 50% and 100% proportionally reduced the compressive strength due to the increase in porosity caused by the waste, especially in the group of mortars with the simple activator, and included the formation of efflorescence. On the other hand, the compound activator increased the packing of the particles in the mortar, as observed in the images of the microstructure. This reduced porosity inhibited efflorescence and resulted in higher resistances that reached a maximum value of 22.68 MPa at 28 days in the group of 50% mortars with the compound activator. Therefore, the study showed that there is potential for the replacement of sand with plastic waste for the production of mortars, which can be considered a more sustainable building material.

2.
Cir Cir ; 89(6): 769-775, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34851584

RESUMEN

OBJECTIVE: Determinate instant and after 1-month non-dipper effect in hypertense patients after renal transplant by 24-hour ambulatory blood pressure monitoring in Hospital General de Zona No. 50, San Luis Potosí, Mexico. METHOD: Descriptive, longitudinal and prospective cohort study of a non-probability convenience sampling in post-transplant patients with hypertension. We collected data from MAPA and includes age, sex, cardiovascular risk factors in variables. Use of central tendency and dispersion measures for descriptive analysis and t Student for inferential analysis. RESULTS: 19 patients were included, 11 male (57.9%) and 8 females (42.1%), with age range 20 to 49 years (median of 30.2 years ± 7.7). Where the non-dipper effect in the first take was 89.5% and in the second take 84.2%. CONCLUSIONS: There is a high frequency of the non-dipper pattern in patients at one month of kidney transplant, the persistence of this hypertension may be, among others, by the use of immunosuppressants. A new category for non-dipper classification is described.


OBJETIVO: Determinar el efecto non-dipper inmediato y posterior a 1 mes en pacientes adultos hipertensos postrasplante renal con monitoreo continuo de la presión arterial de 24 horas, en el Hospital General de Zona No. 50 de San Luis Potosí, México. MÉTODO: Estudio de tipo cohorte, longitudinal, prospectivo, con muestreo no probabilístico por conveniencia de casos consecutivos en pacientes receptores de trasplante renal con hipertensión arterial. Se recogieron los siguientes datos: edad, sexo, factores de riesgo cardiovascular, uso de antihipertensivos o inmunosupresores, y monitoreo ambulatorio de la presión arterial de 24 horas. Se aplicaron medidas de tendencia central y de dispersión para análisis descriptivo, y prueba t de Student para análisis inferencial. RESULTADOS: Se incluyeron 11 hombres (57.9%) y 8 mujeres (42.1%), con una edad de 20 a 49 años (media 30.2 ± 7.7), en los que el efecto non-dipper inmediato fue del 89.5% y posterior a 1 mes fue del 84.2%. CONCLUSIONES: Existe una alta frecuencia del patrón non-dipper en pacientes a 1 mes del trasplante renal. La persistencia de la hipertensión puede ser, entre otras causas, por el uso de inmunosupresores. Se describe una nueva categoría para la clasificación non-dipper.


Asunto(s)
Hipertensión , Trasplante de Riñón , Adulto , Monitoreo Ambulatorio de la Presión Arterial , Ritmo Circadiano , Femenino , Humanos , Hipertensión/tratamiento farmacológico , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Adulto Joven
3.
Biomedicine (Taipei) ; 11(2): 1-4, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-35223397

RESUMEN

OBJECTIVES: COVID-19 outbreak brings a challenge to healthcare systems. The sex, age, and cardiometabolic comorbidities have been considered risk factors for disease severity. To evaluate the association between risk factors with death as well the risk of death in hospitalized COVID-19 patients. METHODS: The present cross-sectional cohort study, includes hospitalized SARS-CoV-2 confirmed cases. Data analysis was performed using the National COVID-19 Cases Report Database. Pearson's χ2 test and odds ratios (95% CI) were calculated to determine the association between variables. Thereafter, risk of death was evaluated by Cox proportional hazards model. RESULTS: A total of 67 328 inpatients were included; mean age 55.29 years (±15.97). Of total, 42 164 (62.62%) were men, 6 349 (9.43%) were intubated, and 23 873 (35.46%) died. Male sex, age older than 60 years, and cardiometabolic comorbidities were associated with death. Hazard ratio for death in older intubated patients was lower than in non-intubated (HR 1.242, 95%CI, 1.167-1.322; P < 0.001) and (HR 2.128, 95%CI, 2.066-2.193; P < 0.001) respectively. CONCLUSIONS: Tracheal intubation or not is the most important predictor for death in COVID-19 infected patients in this Mexican cohort. Already known risk factors for COVID-19 severity may become less relevant once patients require tracheal intubation.

4.
ACS Omega ; 5(25): 14879-14889, 2020 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-32637762

RESUMEN

The modification of CeO2 with rare-earth elements opens up a wide range of applications as biomedical devices using infrared emission as well as magnetic and gas-sensing devices, once the structural, morphological, photoluminescent, magnetic, electric, and gas-sensing properties of these systems are strongly correlated to quantum electronic transitions between rare-earth f-states among defective species. Quantitative phase analysis revealed that the nanopowders are free from secondary phases and crystallize in the fluorite-type cubic structure. Magnetic coercive field measurements on the powders indicate that the substitution of cerium with lanthanum (8 wt %), in a fluorite-type cubic structure, created oxygen vacancies and led to a decrease in the fraction of Ce species in the 3+ state, resulting in a stronger room-temperature ferromagnetic response along with high coercivity (160 Oe). In addition to the magnetic and photoluminescent behavior, a fast response time (5.5 s) was observed after CO exposure, indicating that the defective structure of ceria-based materials corresponds to the key of success in terms of applications using photoluminescent, magnetic, or electrical behaviors.

5.
PLoS One ; 10(9): e0137541, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26398115

RESUMEN

We present the first study of density and apparent survival for a jaguar (Panthera onca) population in northern Mexico using 13 years of camera trap data from 2000 to 2012. We used the Barker robust design model which combines data from closed sampling periods and resight data between these periods to estimate apparent survival and abundance. We identified 467 jaguar pictures that corresponded to 48 jaguar individuals. We included camera type and field technician as covariates for detection probabilities. We used three covariates to evaluate the effect of reserve on jaguar apparent survival: i) private reserve creation ii) later reserve expansions, and iii) cattle ranches' conservation activities. We found that the use of digital cameras in addition to film cameras increased detection probability by a factor of 6x compared with the use of only film cameras (p = 0.34 ± 0.05 and p = 0.05 ± 0.02 respectively) in the closed period and more than three times in the open period (R = 0.91 ± 0.08 and R = 0.30 ± 0.13 mixed and film cameras respectively). Our availability estimates showed no temporary emigration and a fidelity probability of 1. Despite an increase of apparent survival probability from 0.47 ± 0.15 to 0.56 ± 0.11 after 2007, no single covariate explained the change in these point estimates. Mean jaguar density was 1.87 ± 0.47 jaguars/100 km2. We found that 13 years of jaguar population monitoring with our sampling size were not enough for detecting changes in survival or density. Our results provide a baseline for studies evaluating the effectiveness of protected areas and the inclusion of ranch owners in jaguar conservation programs and long-term population viability.


Asunto(s)
Conservación de los Recursos Naturales , Panthera/fisiología , Animales , Femenino , Geografía , México , Densidad de Población , Análisis de Supervivencia
6.
Int J Dev Neurosci ; 26(5): 497-503, 2008 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18394855

RESUMEN

The present results show that the expression of Growth Arrest Specific1 (Gas1) in SH-SY5Y neuroblastoma cells significantly inhibits the increased phosphorylation of tyrosine 1062 of the Ret receptor tyrosine kinase induced by glial-cell-line-derived neurotrophic factor (GDNF). We also observed that Gas1 significantly reduces the activation of Akt. GDNF and members of its family of ligands (GFLs), signal through a molecular complex consisting of one of its receptors (GFRalphas) and the Ret receptor tyrosine kinase. GDNF is a key component to preserve several cell populations in the nervous system, including dopaminergic and motor neurons, and also participates in the survival and differentiation of peripheral neurons such as enteric, sympathetic and parasympathetic. On the other hand, Gas1 is a molecule involved in cell arrest that can induce apoptosis when over-expressed in different cell lines, including cells of neuronal and glial origin. Although, Gas1 is widely expressed during development, its role in vivo has not yet been clearly defined. We recently showed the structural homology between Gas1 and GFRalphas, thus suggesting that the physiological role of Gas1 is that of modulating the biological responses induced by GDNF and/or other members of this family of signaling molecules. The results of this work are consistent with the hypothesis of Gas1 acting as a negative modulator of GDNF signaling.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Factor Neurotrófico Derivado de la Línea Celular Glial/farmacología , Proteínas de la Membrana/metabolismo , Proteínas Proto-Oncogénicas c-ret/metabolismo , Transducción de Señal/efectos de los fármacos , Tirosina/metabolismo , Apoptosis , Western Blotting , Proteínas de Ciclo Celular/farmacología , Línea Celular Tumoral , Activación Enzimática/efectos de los fármacos , Proteínas Ligadas a GPI , Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Receptores del Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Humanos , Inmunoquímica , Proteínas de la Membrana/farmacología , Factores de Crecimiento Nervioso/genética , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-ret/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA