Self-Assembly Behavior of Amphiphilic Janus Dendrimers in Water: A Combined Experimental and Coarse-Grained Molecular Dynamics Simulation Approach

Indexación: Scopus.Acknowledgments: M.E.E.G. thank the Ph. D. scholarship (251115) from CONACyT. The authors would like to thank: Luis Elizalde-Herrera (CIQA) for his help running the NMR spectra; Gloria Macedo-Raygoza and Miguel J. Beltrán-García (UAG), for their help in the measuring of MALDI-TOF mass spectra; and Maricela Rodríguez-Nieto and Jorge Luis Menchaca (UANL), for their help with the AFM measurements. FDGN thanks to the USA Air Force Office of Scientific Research Awards.Amphiphilic Janus dendrimers (JDs) are repetitively branched molecules with hydrophilic and hydrophobic components that self-assemble in water to form a variety of morphologies, including vesicles analogous to liposomes with potential pharmaceutical and medical application. To date, the self-assembly of JDs has not been fully investigated thus it is important to gain insight into its mechanism and dependence on JDs’ molecular structure. In this study, the aggregation behavior in water of a second-generation bis-MPA JD was evaluated using experimental and computational methods. Dispersions of JDs in water were carried out using the thin-film hydration and ethanol injection methods. Resulting assemblies were characterized by dynamic light scattering, confocal microscopy, and atomic force microscopy. Furthermore, a coarse-grained molecular dynamics (CG-MD) simulation was performed to study the mechanism of JDs aggregation. The obtaining of assemblies in water with no interdigitated bilayers was confirmed by the experimental characterization and CG-MD simulation. Assemblies with dendrimersome characteristics were obtained using the ethanol injection method. The results of this study establish a relationship between the molecular structure of the JD and the properties of its aggregates in water. Thus, our findings could be relevant for the design of novel JDs with tailored assemblies suitable for drug delivery systems. © 2018 by the authors.https://www.mdpi.com/1420-3049/23/4/96

Hypoalbuminemia in the outcome of patients with non-variceal upper gastrointestinal bleeding

AbstractIntroduction and aimThe role of serum albumin level in patients with non-variceal upper gastrointestinal bleeding (NVUGB) has not been extensively studied. Our aim was to evaluate the role of serum albumin on admission in terms of in-hospital mortality in patients with NVUGB.Materials and methodsPatients admitted with NVUGB during a 4-year period were prospectively included. Demographic, clinical, and laboratory data were collected. ROC curve analysis was used to determine the cutoff value for serum albumin on admission that made a distinction between deceased patients and survivors with respect to serum albumin on admission, as well as its overall performance compared with the Rockall score.Results185 patients with NVUGB were evaluated. Men predominated (56.7%) and a mean age of 59.1±19.9 years was found. Mean serum albumin on admission was 2.9±0.9g/dl with hypoalbuminemia (< 3.5g/dl) detected on admission in 71.4% of cases. The ROC curve found that the best value for predicting hospital mortality was an albumin level of 3.1g/dl (AUROC 0.738). Mortality in patients with albumin ≥ 3.2g/dl was 1.2% compared with 11.2% in patients with albumin<3.2g/dl (P=.009; OR 9.7, 95%CI 1.2-76.5). There was no difference in overall performance between the albumin level (AUORC 0.738) and the Rockall score (AUROC 0.715) for identifying mortality.ConclusionsPatients with hypoalbuminemia presenting with NVUGB have a greater in-hospital mortality rate. The serum albumin level and the Rockall score perform equally in regard to identifying the mortality rate

Co-limitation towards lower latitudes shapes global forest diversity gradients

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers

Prueba del perfil de textura en barra energética de nopal y variación de cereales

Man as an evaluation instrument, plays a very important role in the sensory evaluation of food that although in fact that science and technology progress day after day, consequently all the measuring instruments in a food analysis laboratory become indispensable, for the evaluation of the texture profile, the human being is the main measuring instrument, however with one it is not enough, so in this project 10 judges who previously received their training for 6 months were located. The completely randomized experimental design of three treatments with five repetitions was elaborated, which were subjected to the sensory analysis to determine the texture test, and thus choose the best formula to proceed to the next stage in the project. Giving as a result that the treatment two since it is the one that is intermediate in all the tests of the profile of flavor and texture.El hombre como instrumento de evaluación, funge un papel muy importante en la evaluación sensorial de los alimentos que si bien es cierto que la ciencia y tecnología avanzan día tras día, por consecuencia todos los instrumentos de medición en un laboratorio de análisis de alimentos se vuelven indispensables, para la evaluación del perfil de textura es el ser humano el principal instrumento de medición, sin embargo con uno no es suficiente, así que en este proyecto se localizaron 10 jueces que previamente recibieron su entrenamiento durante 6 meses. Se elaboró el diseño experimental completamente al azar de tres tratamientos con cinco repeticiones, los cuales se sometieron al análisis sensorial para determinar el test de textura, y así elegir la mejor fórmula para proseguir a la siguiente etapa en el proyecto. Dando como resultado que el tratamiento dos es el que se encuentra intermedio en todas las pruebas del perfil de sabor y textura

Effect of antispasmodic agents, alone or in combination, in the treatment of Irritable Bowel Syndrome: Systematic review and meta-analysis

Introduction: Irritable bowel syndrome (IBS) is characterized by recurrent abdominal pain, bloating, and changes in bowel habit. Aims: To determine the clinical effectiveness of the antispasmodic agents available in Mexico for the treatment of IBS. Methods: We carried out a systematic review and meta-analysis of randomized controlled clinical trials on antispasmodic agents for IBS treatment. Clinical trials identified from January 1960 to May 2011 were searched for in MEDLINE, the Cochrane Library, and in the ClinicalTrials.gov registry. Treatment response was evaluated by global improvement of symptoms or abdominal pain, abdominal distention/bloating, and frequency of adverse events. The effect of antispasmodics vs placebo was expressed in OR and 95% CI. Results: Twenty-seven studies were identified, 23 of which fulfilled inclusion criteria. The studied agents were pinaverium bromide, mebeverine, otilonium, trimebutine, alverine, hyoscine, alverine/simethicone, pinaverium/simethicone, fenoverine, and dicyclomine. A total of 2585 patients were included in the meta-analysis. Global improvement was 1.55 (CI 95%: 1.33 to 1.83). Otilonium and the alverine/simethicone combination produced significant values in global improvement while the pinaverium/simethicone combination showed improvement in bloating. As for pain, 2394 patients were included with an OR of 1.52 (IC 95%: 1.28 a 1.80), favoring antispasmodics. Conclusions: Antispasmodics were more effective than placebo in IBS, without any significant adverse events. The addition of simethicone improved the properties of the antispasmodic agents, as seen with the alverine/simethicone and pinaverium/simethicone combinations

Métodos de conservação de amostras de leite para determinação da contagem bacteriana total por citometria de fluxo Milk sample conservation methods to determine the total bacteria count by flow cytometry

Avaliou-se o efeito da temperatura de armazenamento e da idade da amostra sobre a contagem bacteriana total de amostras de leite conservadas com azidiol para verificar a possibilidade de utilização de uma única amostra nas análises previstas na Instrução Normativa 51 (IN-51). Utilizaram-se 320 alíquotas de leite coletado de um tanque de expansão para avaliação de três temperaturas de armazenamento - a 0 ºC (congelada), 7 ºC (refrigerada) e 24 ºC (à temperatura ambiente) -, três tipos de conservação (bronopol, azidiol e sem conservante) e quatro idades da amostra (1, 3, 5 e 7 dias). Para contagem bacteriana total, foram consideradas controle amostras refrigeradas, com azidiol e amostras de um dia e, para composição e contagem de células somáticas (CCS), os controles foram amostras refrigeradas, com bronopol e de um dia. Nas amostras conservadas com bronopol, a contagem bacteriana total foi menor que na controle, independentemente da idade e da temperatura. O mesmo foi observado nas amostras com azidiol e congeladas. Amostras com azidiol apresentaram aumento da contagem bacteriana total, independentemente da idade, enquanto, naquelas que não receberam azidiol, a contagem bacteriana total foi superior à das amostras refrigeradas, conservadas com azidiol e de um dia. As amostras conservadas com azidiol e refrigeradas tiveram aumento linear na contagem bacteriana total de 0,0058 log por dia, o que pode ser considerado sem importância prática. Amostras conservadas com azidiol e refrigeradas apresentaram CCS menor, em todas as idades, em relação a amostras refrigeradas e conservadas com bronopol. Os teores de gordura e lactose reduziram após o quinto dia. Foi necessária a coleta de duas amostras: uma destinada à determinação de CCS e da composição contendo bronopol e outra para contagem bacteriana total contendo azidiol. Amostras para contagem bacteriana total podem ser analisadas em até sete dias, se mantidas a 7 ºC e adicionadas de azidiol.<br>The objective of this study was to evaluate the effect of storage temperature and sample age on the total bacterial count (TBC) of milk samples preserved with azidiol to verify whether a single sample could be used to perform regulatory milk analysis under the Normative Instruction 51 (IN-51). Three hundred and twenty milk aliquots were used collected from an expansion tank to assess three storage temperatures (0 ºC - frozen: 7 ºC - refrigerated, and 24 ºC - room temperature), three types of conservation (bronopol, azidiol and no preservative) and four sample ages (1, 3, 5, and 7 days). For the total bacteria count, refrigerated control samples, with azidiol and one day old samples, and for composition and somatic cell count (SCC), the controls were defined as one day old refrigerated samples containing bronopol. Samples conserved with bronopol presented lower total bacteria count than the control regardless of storage temperature and sample age. Milk samples conserved with azidiol and stored refrigerated presented lower SCC, regardless of age, compared to refrigerated samples conserved with bronopol. The fat and lactose contents decreased after the fifth day. Two samples had to be collected: one for SCC determination and composition containing bronopol and another for the total bacteria count containing azidiol. Milk samples used for total bacteria count can be tested up to 7 days if they are kept at 7 ºC with the addition of azidiol

Prevalence of Barrett's esophagus: An observational study from a gastroenterology clinic

Introduction and aims: Barrett's esophagus is a condition that predisposes to esophageal adenocarcinoma. Our aim was to establish the prevalence of Barrett's esophagus at our center, as well as determine its associated factors. Materials and methods: We retrospectively assessed the endoscopic reports of 500 outpatients seen at our Gastroenterology Service from November 2014 to April 2016. We determined the prevalence of Barrett's esophagus and analyzed the demographic, clinical, and endoscopic findings associated with that pathology. Results: The prevalence of Barrett's esophagus was 1.8%. The mean age of the patients with Barrett's esophagus was 58.7 years (range: 45-70) and there was a predominance of men (66%). In the subgroup of patients with symptoms of gastroesophageal reflux (n = 125), Barrett's esophagus prevalence was 7.2%. In the multivariate analysis, the factors that were independently associated with Barrett's esophagus were gastroesophageal reflux (P=.005) and hiatal hernia (P=.006). Conclusions: The overall prevalence of Barrett's esophagus was 1.8% in our population, with a prevalence of 7.2% in patients that had symptoms of gastroesophageal reflux. Resumen: Introducción y objetivos: El esófago de Barrett es una condición que predispone al adenocarcinoma esofágico. Nuestro objetivo fue establecer la prevalencia de esófago de Barrett en nuestro centro, así como los factores asociados a esta condición. Material y métodos: Evaluamos retrospectivamente los reportes de 500 endoscopias superiores de pacientes ambulatorios de nuestro Servicio de Gastroenterología entre noviembre del 2014 y abril del 2016. Se determinó la prevalencia de esófago de Barrett y se analizaron los datos demográficos, clínicos y endoscópicos asociados a esta patología. Resultados: La prevalencia de esófago de Barrett fue del 1.8%. La edad media en los pacientes con esófago de Barrett fue de 58.7 años (rango: 45-70), con predominancia del sexo masculino (66%). En el subgrupo de pacientes con síntomas de reflujo gastroesofágico (n = 125) la prevalencia de esófago de Barrett fue del 7.2%. En el análisis multivariado los factores asociados a esófago de Barrett de forma independiente fueron: síntomas de reflujo gastroesofágico (p = 0.005) y hernia hiatal (p = 0.006). Conclusión: La prevalencia global de esófago de Barrett es del 1.8% en nuestra población, con una prevalencia del 7.2% en pacientes con síntomas de reflujo gastroesofágico. Keywords: Intestinal metaplasia, Adenocarcinoma, Gastroesophageal reflux, Hiatal hernia, Endoscopy, Palabras clave: Metaplasia intestinal, Adenocarcinoma, Reflujo gastroesofágico, Hernia hiatal, Endoscopi

Three-Dimensional Extrusion Printing of Porous Scaffolds Using Storable Ceramic Inks

Contains fulltext : 220575.pdf (Publisher’s version ) (Closed access)In this study, we describe the additive manufacturing of porous three-dimensionally (3D) printed ceramic scaffolds prepared with hydroxyapatite (HA), beta-tricalcium phosphate (beta-TCP), or the combination of both with an extrusion-based process. The scaffolds were printed using a novel ceramic-based ink with reproducible printability and storability properties. After sintering at 1200 degrees C, the scaffolds were characterized in terms of structure, mechanical properties, and dissolution in aqueous medium. Microcomputed tomography and scanning electron microscopy analyses revealed that the structure of the scaffolds, and more specifically, pore size, porosity, and isotropic dimensions were not significantly affected by the sintering process, resulting in scaffolds that closely replicate the original dimensions of the 3D model design. The mechanical properties of the sintered scaffolds were in the range of human trabecular bone for all compositions. All ceramic bioinks showed consistent printability over a span of 14 days, demonstrating the short-term storability of the formulations. Finally, the mass loss did not vary among the evaluated compositions over a period of 28 days except in the case of beta-TCP scaffolds, in which the structural integrity was significantly affected after 28 days of incubation in phosphate-buffered saline. In conclusion, this study demonstrates the development of storable ceramic inks for the 3D printing of scaffolds of HA, beta-TCP, and mixtures thereof with high fidelity and low shrinkage following sintering that could potentially be used for bone tissue engineering in load-bearing applications

Barrett's esophagus: Ten years of experience at a tertiary care hospital center in Mexico

Introduction: The prevalence of Barrett's esophagus has been calculated at between 1.3 and 1.6%. There is little information with respect to this in Mexico. Aim: To determine the frequency and characteristics of Barrett's esophagus in patients that underwent endoscopy at a national referral center, within a 10-year time frame. Material and methods: The databases of the pathology and gastrointestinal endoscopy departments of the Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán” were analyzed, covering the period of January 2002 to December 2012. Patients with a histologic diagnosis of Barrett's esophagus were included. The variables of age, sex, the presence of dysplasia/esophageal adenocarcinoma, Barrett's esophagus length, and follow-up were analyzed. Results: Of 43,639 upper gastrointestinal endoscopies performed, 420 revealed Barrett's esophagus, corresponding to a frequency of 9.6 patients for every 1,000 endoscopies. Of those patients, 66.9% (n = 281) were men, mean patient age ± SD was 57.2 ± 15.3 years, 223 patients (53%) presented with long-segment Barrett's esophagus, and 197 (47%) with short-segment Barrett's esophagus. Dysplasia was not present in 339 patients (80.7%). Eighty-one (19.3%) patients had some grade of dysplasia or cancer: 48/420 (11.42%) presented with low-grade dysplasia, 20/420 (4.76%) with high-grade dysplasia, and 13/420 (3.1%) were diagnosed with esophageal cancer arising from Barrett's esophagus. Mean follow-up time was 5.6 years. Conclusions: The frequency of Barrett's esophagus was 9.6 cases for every 1,000 upper gastrointestinal endoscopies performed. Dysplasia was not documented in the majority of the patients with Barrett's esophagus and they had no histopathologic changes during follow-up. A total of 19.3% of the patients presented with dysplasia or cancer