An increase in intracellular Ca2+ concentration (Ca2+i) plays a key role in controlling endothelial functions; however, it is still unclear whether endothelial Ca2+ handling is altered by type 2 ...diabetes mellitus, which results in severe endothelial dysfunction. Herein, we analyzed for the first time the Ca2+ response to the physiological autacoid ATP in native aortic endothelium of obese Zucker diabetic fatty (OZDF) rats and their lean controls, which are termed LZDF rats. By loading the endothelial monolayer with the Ca2+-sensitive fluorophore, Fura-2/AM, we found that the endothelial Ca2+ response to 20 µM and 300 µM ATP exhibited a higher plateau, a larger area under the curve and prolonged duration in OZDF rats. The “Ca2+ add-back” protocol revealed no difference in the inositol-1,4,5-trisphosphate-releasable endoplasmic reticulum (ER) Ca2+ pool, while store-operated Ca2+ entry was surprisingly down-regulated in OZDF aortae. Pharmacological manipulation disclosed that sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) activity was down-regulated by reactive oxygen species in native aortic endothelium of OZDF rats, thereby exaggerating the Ca2+ response to high agonist concentrations. These findings shed new light on the mechanisms by which type 2 diabetes mellitus may cause endothelial dysfunction by remodeling the intracellular Ca2+ toolkit.
La relación ahusamiento-volumen es indispensable para la planeación del manejo silvícola en los bosques con la finalidad de favorecer la distribución de los productos. Por esta razón, el objetivo del ...presente estudio fue generar un modelo compatible que permitiera estimar de forma precisa el volumen-ahusamiento de Abies religiosa en varias regiones de México. Se utilizaron 2608 datos en el análisis de la información y el modelo se ajustó simultáneamente mediante la regresión aparentemente no relacionada (RAN) para la estimación de parámetros compatibles. El modelo generó coeficientes de determinación ajustados superiores al 97 %, raíces del medio cuadrático menores al 0.40, sesgos menores a 0.11, con certeza para modelar cada región forestal; datos que fueron complementados con sus respectivos criterios de información Akaike (AIC). En la mayoría de casos el factor de forma de la especie fue neiloide a paraboloide, información que será de utilidad para la elaboración de inventarios forestales.
Background: Climate change is becoming more evident, and distribution models are useful tools to predict the effect it might cause on biodiversity.
Hypotheses: Under climate change scenarios, ...temperate forests species of the genus Pinus and Quercus will undergo reductions in their distribution area and changes in their spatial pattern.
Studied species: Arbutus xalapensis, Clethra mexicana, Pinus devoniana, Pinus oocarpa, Pinus teocote, Quercus acutifolia, Quercus castanea, Quercus crassifolia, Quercus elliptica, Quercus magnoliifolia and Quercus rugosa.
Study site: Oaxaca
Methods: Two scenarios were constructed, an optimistic one (SSP-1 and RCP 2-6) and a pessimistic one (SSP-5 and RCP 8.5) for the years 2030 and 2090. A total of 1,383 records and eight bioclimatic variables were used, along with seven learning algorithms, evaluated using ROC and TSS metrics.
Results: An ensemble model was obtained, in which the most important contributing variables were precipitation of the wettest quarter, mean annual temperature, minimum temperature of the coldest month and annual temperature range. The species that showed the highest ROC values were Clethra mexicana (0.91) and Arbutus xalapensis (0.89) with TSS values of 0.68 and 0.60, respectively.
Conclusions: Regardless of the scenario, by the year 2090 all species of Pinus and Quercus will reduce their potential distribution. Therefore, it is urgent to establish conservation policies.
Las variables diámetro y altura son factores indispensables en inventarios forestales para determinar el volumen que se almacena en el bosque. El objetivo de esta investigación fue generar una ...ecuación para ocho entidades federativas que permita estimar de forma precisa el volumen maderable de Abies religiosa en el centro y sur del país. Se utilizaron 2747 datos para ajustar ecuaciones de volumen rollo total árbol, volumen de ramas y volumen total árbol (vrta, vramas y vta). Para la selección del mejor modelo se fijaron los siguientes criterios: coeficiente de determinación ajustada, sesgo, error medio; así como el análisis gráfico y numérico de los residuales. Debido a la falta de información de las ramas para las entidades de Tlaxcala y Veracruz solo se obtuvo el volumen rollo total árbol. La bondad de ajuste generada por las ecuaciones es confiable, ya que explican más del 93 % a la variable dependiente, los errores son menores a 0.47 m. Estas expresiones son una herramienta útil que podrá ser aplicada por los técnicos forestales en distintos rodales en la zona de estudio.
Microvascular free-flap reconstruction is one of the treatment options after large resection of head and neck neoplasms. The objectives of this study are to identify short-term outcomes and risk ...factors for flap complication in patients who underwent neoplasms resection of head and neck with microvascular free-flap reconstruction.
Retrospective study of patients who underwent surgery for head and neck neoplasm with microvascular free-flap reconstruction between January 2014-2020. Complications were studied at 30-days follow-up and divided into medical and flap complications. Factors independently associated with flap complication were analyzed.
We included 31 patients (15 men). The mean age was 60 years. Reconstruction was performed with radial-forearm flap in 74% (n=23) and with free-fibula flap in 26% (n=8). Mean surgical time was 420 minutes. Median hospital length of stay was 7 days. Medical complications were of 23%. Minor complications were of 35% and major of 32%. There was no mortality in 30-days follow-up. Flap complications were of 35%. Reintervention was of 29%, surgical site infection of 9%, dehiscence of 29% and flap loss of 9.7%. Surgical site infection was independently associated with prolonged surgical time (Odds ratio OR=1.03, IC95%=0.98-1.04, p=0.02) and body mass index equal to or greater than 30 (OR=1.38, IC95%=0.84-2.26, p=0.04) while flap loss was associated with prolonged surgical time (OR=1.02, IC95%=0.99-1.04, p=0.01).
Microsurgical free-flap reconstruction should be considered in our population in patients with large head and neck neoplasms. Preoperative assessment of the risk of postoperative complications is essential before selecting patients for this surgery.
This paper presents a performance evaluation of the scalable video streaming over mobile ad hoc networks. In particular, we focus on the rate-adaptive method for streaming scalable video (H.264/SVC). ...For effective adaptation a new cross-layer routing protocol is introduced. This protocol provides an efficient algorithm for available bandwidth estimation. With this information, the video source adjusts its bit rate during the video transmission according to the network state. We also propose a free simulation framework that supports evaluation studies for scalable video streaming. The simulation experiments performed in this study involve the transmission of SVC streams with Medium Grain Scalability (MGS) as well as temporal scalability over different network scenarios. The results reveal that the rate-adaptive strategy helps avoid or reduce the congestion in MANETs obtaining a better quality in the received videos. Additionally, an actual ad hoc network was implemented using embedded devices (Raspberry Pi) in order to assess the performance of the proposed adaptive transmission mechanism in a real environment. Additional experiments were carried out prior to the implementation with the aim of characterizing the wireless medium and packet loss profile. Finally, the proposed approach shows an important reduction in energy consumption, as the study revealed.
Direct Acting Antivirals (DAAs) represent a large improvement in the treatment of chronic hepatitis C, resulting in <90% sustained virological response (SVR). There are no reports on the real-world ...DAA response for Mexico and few reports exist for Latin America. The aim of the study was to report SVR, and immediate benefits with the DAA treatments sofosbuvir, ledispavir, with/without ribavirin (SOF/LDV ± RBV) and ombitasvir, paritaprevir, ritonavir, dasabuvir with/without RBV (OBV/PTV/r/DSV ± RBV) in patients with viral genotype 1a or 1b, and who did not respond to previous peginterferon/ribavirin (PegIFNα2a+RBV) therapy.
A descriptive, ambispective, longitudinal study was conducted. A cohort of 261 adult patients received PegIFNα2a+RBV therapy before 2014; 167 (64%) did not respond, 83 of these were subsequently treated with SOF/LDV ± RBV or OBV/PTV/r/DSV ± RBV. Child-Pugh-Score (CPS), Fibrosis-4 (FIB-4), and AST to Platelet Ratio Index (APRI) were evaluated before and after treatment.
SVR with PegIFNα2a+RBV was 36%, and 97.5% with DAAs. CPS, FIB-4 and APRI improved significantly after DAA treatment, mainly because of liver transaminase reduction.
DAA treatment showed excellent SVR rates in Mexican patients who had not responded to PegIFNα2a+RBV therapy. Improvement in CPS, FIB-4 and APRI without improvement in fibrosis was observed in cirrhotic and non-cirrhotic patients, as well as considerable reduction in liver transaminases, which suggests a reduction in hepatic necroinflammation.
Abstract Introduction: Volume is an important variable in forest management since it allows evaluating the growth and development of individuals in stands. Objective: To analyze the techniques for ...estimating forest volume with an emphasis on the tropics. Materials and methods: The work was developed with the non-probabilistic snowball technique, in which the bibliography reported in an investigation suggested the search for similar works to enrich the subject. Results and discussion: In tropical forests, tree measurement variables provide valuable information for estimating stem or total volume using a xylometer, Pressler and standing tree volume formulas, dendrometric bodies, rigorous volume estimation, graphical method or conventional equations and neural networks. Accurate volume information is only obtained with the xylometer technique, which is the only one that allows estimating volume using the direct method. The rigorous volume estimation technique is the most used in the tropics to obtain the volume of individual sections, which are fitted by conventional or neural network equations to estimate the total volume. Most researchers selected the best models using the coefficient of determination, root mean square error, bias, Durbin-Watson test, and Akaike and Bayesian information criteria. Conclusion: Model selection depends directly on the researchers; however, the xylometer technique is the only one that estimates volume with the direct method and in an accurate way.
Introducción: Existe poca evidencia que detalle el comportamiento de cada variable espacio-temporal del patrón de carrera utilizando diferentes superficies. Objetivo: Comparar las variables ...espaciotemporales del patrón de carrera de futbolistas adolescentes en superficie natural y artificial. Método: se realizó un estudio de corte transversal con 18 jugadores de fútbol masculino (edad mediana= 12 años; Rango intercuartílico RIC 12-13). Mediante un sistema de medición óptico de 5 metros de longitud se analizó velocidad, aceleración, tiempo de contacto (Tc), tiempo de vuelo (Tv), fase de contacto, fase de apoyo, propulsión, zancada y cadencia. Las valoraciones fueron inicialmente desarrolladas en Superficie Artificial (SA) y 24 horas después en Superficie Natural (SN). Se utilizaron las pruebas Rangos con signos de Wilcoxon para datos pareados y el coeficiente de correlación de Spearman. Resultados: La SA mostró una fase de apoyo fue superior a la SN (SN: Me=0,05 RIC:0,03; 0,06; SA: Me=0,09 RIC 0,08;0,10; p <0,001). El Tv (SN: Me=0,16 RIC:0,14;0,19; SA: Me=0,04 RIC: 0,04;0,05; p<0,001), la fase de contacto (SN: Me=0,02 RIC:0,02;0,03; SA: Me=0,02 RIC: 0,01;0,02; p=0,040) y la propulsión (SN: Me=0,14 RIC:0,09;0,17; SA: Me=0,07 RIC:0,06;0,09; p=<0,001) fueron mayores en SN que en SA. Se encontró una relación indirecta entre velocidad y fase de contacto en SN. El Tv y la zancada se asociaron indirectamente con la aceleración en SA. Conclusión: el patrón de carrera varía según la superficie utilizada. La fase de contacto puede explicar la velocidad en la SN; mientras que el Tv y la zancada pueden explicar la aceleración en la SA.
PDF
