943 research outputs found
Electrochemically site-selective alkoxylation of twisted 2-arylbenzoic acids via spirolactonization
The Electrochemical Cross-Dehydrogenative Coupling (ECDC) of twisted biphenyl-2-carboxylic acids with aliphatic alcohols provides 4′-alkoxyspirolactones which isomerize, under mild basic conditions, to give 4′-alkoxy-2-phenylbenzoic acids. This site-selective alkoxylation was readily adapted to 1 mmol scale and is environmentally friendly, as no terminal oxidants are needed and H2 is the only residue. The suitability of diphenic acid derivatives in this two-step protocol is noteworthy, especially for axially chiral substrates that can be functionalized with retention of the configuration and of the enantiomeric purity. We have proposed a plausible mechanism based on experimental pieces of evidence that support the single-electron oxidation of the carboxylate, formed by deprotonation of the biphenyl-2-carboxylic acids with 2,6-lutidine, and DFT calculations that suggest a very fast spirocyclization of the intermediate σ-aroyloxyl radical. Competing pathways to benzocoumarins were also examined by computational studies.This work was generously supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICIU; grant no. CTQ2017-88171-P) and the University of Alicante (grant no. VIGROB-285/19). I. B. acknowledges the Spanish MICIU for a Juan de la Cierva-incorporación grant (no. IJCI-2017-33706)
Adaptive Control Optimization of Cutting Parameters for High Quality Machining Operations Based on Neural Networks and Search Algorithms
This book chapter presents an Adaptive Control with Optimization (ACO) system for optimising a multi-objective function based on material removal rate, quality loss function related to surface roughness, and cutting-tool life subjected to surface roughness specifications constraint
Puente Tensairity para pasarela peatonal en el PMT-UPC de Castelldefels (737-PRO-CA-5385)
Actualmente el espacio formado por el “Parc Mediterrani de la Tecnologia” y el
Campus Universitario de la Universitat Politècnica de Catalunya (PMT-UPC) de
Castelldefels está en expansión. Es por ello que se está pensando en la construcción
de dos pasarelas peatonales para cruzar la laguna de laminación de la “Olla del Rei”,
conectando de esta forma el PMT-UPC con el paseo del Pitort. Dado que el PMT-UPC
pretende ser un referente ambiental y tecnológico, se plantea como alternativa óptima
la construcción de una pasarela peatonal ligera diseñada mediante una novedosa
tecnología neumática conocida y patentada con el nombre de Tensairity®.
Las estructuras ligeras son un reto para el ingeniero estructural y un importante
avance hacia una arquitectura sostenible. Tensairity® es un concepto que hace
referencia a estructuras neumáticas ligeras basadas en una sutil interacción entre
cables, elementos de compresión, membranas y aire a baja presión. En Tensairity®,
compresión y tracción están físicamente separados por una membrana de tejido
hinchada a baja presión, el fin de la cual es, por un lado pretensar el elemento de
tracción, y por el otro estabilizar el elemento de compresión frente al pandeo. Esto
permite llevar al material hasta su límite plástico, tanto para tracción como para
compresión, dando como resultado vigas que pueden ser varios órdenes de magnitud
más ligeras que las vigas metálicas convencionales, manteniendo siempre su misma
capacidad de carga. Aplicaciones ideales para esta tecnología son cerchas,
estructuras con grandes luces, estructuras temporales, pasarelas peatonales o incluso
estructuras de despliegue rápido para casos de emergencia, entre otras.
La pasarela peatonal objeto de este proyecto está compuesta por dos partes bien
diferenciadas, una pasarela Tensairity® que cruza la laguna de laminación y dos
estructuras de madera a modo de embarcaderos, una a cada lado de la pasarela y
donde ésta se apoya hasta alcanzar los caminos que bordean el trazado de la laguna.
La pasarela Tensairity® está formada por dos vigas Tensairity® compuestas cada una
de ellas por un tubo hinchable de PVC en cuya parte superior se apoya una viga de
madera a modo de elemento de compresión y en su parte inferior una cinta de carga a
modo de elemento de tracción. Sobre estas dos vigas se sustenta la superestructura
de la pasarela formada por vigas transversales de madera sobre las que se apoya el
tablero y las barandillas, también de madera. Las estructuras de apoyo se construyen
igualmente en madera, con una tipología estructural similar al de la pasarela y
mediante el uso de pilotes que recuerda en cierta manera los embarcaderos presentes
en los ríos, de forma que la estructura completa esté integrada en el entorno
Predicting functionality of protein–DNA interactions by integrating diverse evidence
Chromatin immunoprecipitation (ChIP-chip) experiments enable capturing physical interactions between regulatory proteins and DNA in vivo. However, measurement of chromatin binding alone is not sufficient to detect regulatory interactions. A detected binding event may not be biologically relevant, or a known regulatory interaction might not be observed under the growth conditions tested so far. To correctly identify physical interactions between transcription factors (TFs) and genes and to determine their regulatory implications under various experimental conditions, we integrated ChIP-chip data with motif binding sites, nucleosome occupancy and mRNA expression datasets within a probabilistic framework. This framework was specifically tailored for the identification of functional and non-functional DNA binding events. Using this, we estimate that only 50% of condition-specific protein–DNA binding in budding yeast is functional. We further investigated the molecular factors determining the functionality of protein–DNA interactions under diverse growth conditions. Our analysis suggests that the functionality of binding is highly condition-specific and highly dependent on the presence of specific cofactors. Hence, the joint analysis of both, functional and non-functional DNA binding, may lend important new insights into transcriptional regulation
A 3-year Mediterranean-style dietary intervention may modulate the association between adiponectin gene variants and body weight change
Purpose Adiponectin gene variations have been associated with obesity. There are few interventional studies analyzing this association. The aim of this study was to analyze the effects of a nutritional intervention with Mediterranean-style diet and three
(-4034A/C, +45T/G and +276 G/T) adiponectin gene variants on 3-year body weight changes in high cardiovascular risk patients
Subjects and methods A total of 737 participants, aged 55-80 at high cardiovascular risk were assigned to a low-fat diet or to a Mediterranean-style diet (MD) groups, one with high intake of virgin olive oil (VOO) and the other with high intake of nuts. Anthropometric parameters were taken at baseline and after 3-year follow-up, and the genotyping of the -4034A/C, +45T/G and +276 G/T polymorphisms was done.
Results GG genotype of the +45T/G polymorphism was associated with 3-year higher body weight gain (B=1.399; B=0.043). TT genotype of the +276G/T polymorphism was linked to the highest 3-year body weight gain in men. Both Mediterranean diets appeared to reverse this effect (p for interaction=0.053).
Conclusion Adiponectin gene variation appeared to be associated with 3-year body weight changes in a high cardiovascular risk population. This association may be modulated by a nutritional intervention with a Mediterranean-style diet
Prevalence of Respiratory Polyomaviruses Among Pediatric Patients With Respiratory Symptoms in Singapore
Background: Although WU polyomavirus (WU) and KI polyomavirus (KI) have been demonstrated to infect the human respiratory tract, it remains unclear if WU or KI cause human disease. We sought to further investigate the relationship between WU and KI infection and respiratory disease in a pediatric population with respiratory symptoms in Singapore.Methods: We conducted a cross-sectional study of pediatric patients with respiratory symptoms in a Singaporean pediatrics hospital. Upon consent, residual respiratory samples from pediatric inpatients, previously screened for common respiratory viruses, were collected and further screened for WU and KI using qPCR. The amplicons of positive samples were sequenced for confirmation. The severity of a patient's illness was assessed by chart review post-discharge looking for clinical markers of respiratory status such as presenting symptoms, diagnoses, and interventions.Results: From December 2016 to April 2017, 201 patients with residual respiratory samples were enrolled in the study. The average age of all participants recruited was 45 months. WU and KI were detected in 13% (26/201) and 3% (6/201) of patients, respectively. Conducting bivariate and multivariate modeling, patients with WU or KI positivity were not at increased risk of SARI, need for additional oxygen, intravenous fluids, and did not receive additional oral antibiotics or bronchodilators during admission. In contrast, patients with RSV detections were at increased risk of requiring supplemental oxygen during hospital admission.Conclusion: While limited in sample size, our pilot study data do not support the hypothesis that molecular evidence of WU or KI was associated with increased morbidity among a sample of general, pediatric patients with respiratory illness in Singapore
Optimum sample size to estimate mean parasite abundance in fi sh parasite surveys
[EN] To reach ethically and scientifically valid mean abundance values in parasitological and epidemiological studies this paper considers analytic and simulation approaches for sample size determination. The sample size estimation was carried out by applying mathematical formula with predetermined precision level and parameter of the negative binomial distribution estimated from the empirical data. A simulation approach to optimum sample size determination aimed at the estimation of true value of the mean abundance and its confidence interval (CI) was based on the Bag of Little Bootstraps (BLB). The abundance of two species of monogenean parasites Ligophorus cephali and L. mediterraneus from Mugil cephalus across the Azov-Black Seas localities were subjected to the analysis. The dispersion pattern of both helminth species could be characterized as a highly aggregated distribution with the variance being substantially larger than the mean abundance. The holistic approach applied here offers a wide range of appropriate methods in searching for the optimum sample size and the understanding about the expected precision level of the mean. Given the superior performance of the BLB relative to formulae with its few assumptions, the bootstrap procedure is the preferred method. Two important assessments were performed in the present study: i) based on CIs width a reasonable precision level for the mean abundance in parasitological surveys of Ligophorus spp. could be chosen between 0.8 and 0.5 with 1.6 and 1x mean of the CIs width, and ii) the sample size equal 80 or more host individuals allows accurate and precise estimation of mean abundance. Meanwhile for the host sample size in range between 25 and 40 individuals, the median estimates showed minimal bias but the sampling distribution skewed to the low values; a sample size of 10 host individuals yielded to unreliable estimates.SS and VS were supported by MEDEA project fellowships, Erasmus Mundus Action 2. CC-S was funded by project #MTM2014-52975-C2-1-R:" Inference in Structured Additive Regression (STAR) Models with Extensions to Multivariate Responses. Applications in Biomedicine", cofinanced by the Ministry of Economy and Competitiveness (SPAIN) and by the European Regional Development Fund (FEDER). This study is partially supported by Ministry of Education and Science of Ukraine, project #1/17.Shvydka, S.; Sarabeev, V.; Estruch, VD.; Cadarso-Suarez, C. (2018). Optimum sample size to estimate mean parasite abundance in fi sh parasite surveys. Helminthologia. 55(1):52-59. https://doi.org/10.1515/helm-2017-0054S5259551Rohde, K., Hayward, C., & Heap, M. (1995). Aspects of the ecology of metazoan ectoparasites of marine fishes. International Journal for Parasitology, 25(8), 945-970. doi:10.1016/0020-7519(95)00015-tAnderson, R. M., & Gordon, D. M. (1982). Processes influencing the distribution of parasite numbers within host populations with special emphasis on parasite-induced host mortalities. Parasitology, 85(2), 373-398. doi:10.1017/s0031182000055347Poiani, A. (1992). Ectoparasitism as a possible cost of social life: a comparative analysis using Australian passerines (Passeriformes). Oecologia, 92(3), 429-441. doi:10.1007/bf00317470Kleiner, A., Talwalkar, A., Sarkar, P., & Jordan, M. I. (2014). A scalable bootstrap for massive data. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 76(4), 795-816. doi:10.1111/rssb.12050Jovani, R., & Tella, J. L. (2006). Parasite prevalence and sample size: misconceptions and solutions. Trends in Parasitology, 22(5), 214-218. doi:10.1016/j.pt.2006.02.011BAGGE, A. M., SASAL, P., VALTONEN, E. T., & KARVONEN, A. (2005). Infracommunity level aggregation in the monogenean communities of crucian carp (Carassius carassius). Parasitology, 131(3), 367-372. doi:10.1017/s0031182005007626Belghyti, D., Berrada-rkhami, O., Boy, V., Aguesse, P., & Gabrion, C. (1994). Population biology of two helminth parasites of flatfishes from the Atlantic coast of Morocco. Journal of Fish Biology, 44(6), 1005-1021. doi:10.1111/j.1095-8649.1994.tb01272.xTAYLOR, L. R. (1961). Aggregation, Variance and the Mean. Nature, 189(4766), 732-735. doi:10.1038/189732a
A survey of cost-sensitive decision tree induction algorithms
The past decade has seen a significant interest on the problem of inducing decision trees that take account of costs of misclassification and costs of acquiring the features used for decision making. This survey identifies over 50 algorithms including approaches that are direct adaptations of accuracy based methods, use genetic algorithms, use anytime methods and utilize boosting and bagging. The survey brings together these different studies and novel approaches to cost-sensitive decision tree learning, provides a useful taxonomy, a historical timeline of how the field has developed and should provide a useful reference point for future research in this field
Chronological age interacts with the circadian melatonin receptor 1b gene variation, determining fasting glucose concentrations in mediterranean populations. Additional analyses on type-2 diabetes risk
Gene-age interactions have not been systematically investigated on metabolic phenotypes
and this modulation will be key for a better understanding of the temporal regulation in nutrigenomics.
Taking into account that aging is typically associated with both impairment of the circadian system
and a decrease in melatonin secretion, we focused on the melatonin receptor 1B (MTNR1B)-rs10830963
C>G variant that has been associated with fasting glucose concentrations, gestational diabetes,
and type-2 diabetes. Therefore, our main aim was to investigate whether the association between the
MTNR1B-rs10830963 polymorphism and fasting glucose is age dependent. Our secondary aims were
to analyze the polymorphism association with type-2 diabetes and explore the gene-pregnancies
interactions on the later type-2 diabetes risk. Three Mediterranean cohorts (n = 2823) were analyzed.
First, a cross-sectional study in the discovery cohort consisting of 1378 participants (aged 18 to
80 years; mean age 41 years) from the general population was carried out. To validate and extend
the results, two replication cohorts consisting of elderly individuals were studied. In the discovery
cohort, we observed a strong gene-age interaction (p = 0.001), determining fasting glucose in such
a way that the increasing effect of the risk G-allele was much greater in young (p = 5.9 × 10−10)
than in elderly participants (p = 0.805). Consistently, the association of the MTNR1B-rs10830963
polymorphism with fasting glucose concentrations in the two replication cohorts (mean age over
65 years) did not reach statistical significance (p > 0.05 for both). However, in the elderly cohorts,
significant associations between the polymorphism and type-2 diabetes at baseline were found.
Moreover, in one of the cohorts, we obtained a statistically significant interaction between the MTNR1B polymorphism and the number of pregnancies, retrospectively assessed, on the type-2
diabetes risk. In conclusion, the association of the MTNR1B-rs10830963 polymorphism with fasting
glucose is age-dependent, having a greater effect in younger people. However, in elderly subjects,
associations of the polymorphism with type-2 diabetes were observed and our exploratory analysis
suggested a modulatory effect of the number of past pregnancies on the future type-2 diabetes
genetic risk
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