Nuevo conocimiento - NAT

URI permanente para esta colecciónhttp://hdl.handle.net/10906/78210

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2-Bromo-N-(2-hy-droxy-5-methyl-phen-yl)-2-methyl-propanamide.
(International Union of Crystallography, 2011-09-01) Grande Tovar, Carlos
In the title mol-ecule, C(11)H(14)BrNO(2), there is twist between the mean plane of the amide group and the benzene ring [the C-N-C-C torsion angle is -172.1 (2)°]. The amide H atom forms an intra-molecular hydrogen bond with the Br atom. In the crystal, inter-molecular O-H⋯O and weak C-H⋯O hydrogen bonds link mol-ecules into a chain along [100].
A ‘slow pace of life’ in Australian old-endemic passerine birds is not accompanied by low basal metabolic rates
(Springer Verlag, 2016-05-01) Buttemer, William A.
Life history theory suggests that species experiencing high extrinsic mortality rates allocate more resources toward reproduction relative to self-maintenance and reach maturity earlier (‘fast pace of life’) than those having greater life expectancy and reproducing at a lower rate (‘slow pace of life’). Among birds, many studies have shown that tropical species have a slower pace of life than temperate-breeding species. The pace of life has been hypothesized to affect metabolism and, as predicted, tropical birds have lower basal metabolic rates (BMR) than temperate-breeding birds. However, many temperate-breeding Australian passerines belong to lineages that evolved in Australia and share ‘slow’ life-history traits that are typical of tropical birds. We obtained BMR from 30 of these ‘old-endemics’ and ten sympatric species of more recently arrived passerine lineages (derived from Afro-Asian origins or introduced by Europeans) with ‘faster’ life histories. The BMR of ‘slow’ temperate-breeding old-endemics was indistinguishable from that of new-arrivals and was not lower than the BMR of ‘fast’ temperate-breeding non-Australian passerines. Old-endemics had substantially smaller clutches and longer maximal life spans in the wild than new arrivals, but neither clutch size nor maximum life span was correlated with BMR. Our results suggest that low BMR in tropical birds is not functionally linked to their ‘slow pace of life’ and instead may be a consequence of differences in annual thermal conditions experienced by tropical versus temperate species. © 2016, Springer-Verlag Berlin Heidelberg.
Activity of (2E)-3-(2, 3-dimetoxifenil)-1-(4-metilfenil) prop-2-en-1-ona in the presence of poli(maleic acid-co-2-vinyl-pyrrolidone) on a β-lactamase producing clinical isolate of Staphylococcus aureus
(Universidad de Antioquia, 2012-01-01) Salamanca Mejía, Constaín Hugo
Due to the current problem of resistance to b-lactam antibiotics, it has become necessary, in search of a solution, to work with new molecules with pharmacological potential, and to use novel polymeric systems as matrices or pharmaceutical excipients. Objective: To evaluate the antibiotic activity of ampicillin combined with a synthetic chalcone-type compound, the (2E)-3-(2,3-dimethoxyphenyl)-1-(4- methylphenyl) prop-2-en-1-one, on a clinical isolate of penicillin-resistant Staphylococcus aureus in the presence of a water soluble polymer matrix known as poly(maleic acid-co-2-vinyl-pyrrolidone). Materials and methods: The synthetic compound and the polymeric matrix were obtained by previously described methods. Tests for antibiotic activity against the strain of penicillin-resistant Staphylococcus aureus were done by the broth dilution technique which provided the minimal inhibitory concentrations of the compounds tested. Results: The chalcone-ampicillin mix shows lesser antibiotic effect than the ampicillin-sulbactam used as referent. However, when such mix is combined with the polymer matrix, antibiotic activity significantly increases as evidenced by decrease in the minimal inhibitory concentration with respect to the ampicillin-sulbactam referent.
Acyclic diene metathesis polymerization: History, methods and applications
(Elsevier Ltd, 2017-06-01) Caire da Silva, Lucas
Acyclic Diene Metathesis (ADMET) polymerization was established decades ago and has since developed into a robust and reliable technique. A wide range of different, new materials exhibiting unique properties has been produced via ADMET polymerization since its development. This versatile technique allows, through the right combination of monomer design and choice of catalyst, the synthesis of various functional polymers in addition to a precise control over primary structure. Systematic studies on precise ADMET polymers have greatly contributed to a better understanding of how branch identity and its distribution along the polymer backbone affect the thermal/electronic properties, crystallization, molecular dynamics and morphology of different materials. This article presents an extensive review of how ADMET started, the mechanism that underlies the structural features of ADMET polymers and the different strategies and techniques that have been developed over the years to overcome common synthetic challenges. Monomer synthesis methods are also discussed in detail, providing an important overview of the limitations and advantages of using ADMET as a polymerization technique. Many examples are given of functional ADMET polymers that have been developed by research groups all over the world. © 2016 Elsevier B.V.
Additive partitioning of spider diversity in a fragmented tropical dry forest (Valle del Cauca, Colombia)
(American Arachnological Society, 2010-01-01) Cabra García, Jimmy
Abstract Understanding the variation of diversity patterns requires analysis at multiple spatial scales. In this study we estimated the diversity components (alpha, beta and gamma) of the spider community at El Vínculo Natural Regional Park, using the additive partitioning of diversity (species richness, Shannon's diversity index and Simpson's index) for the first time on this taxon in Colombia. We collected the specimens following a nested sampling design that consisted of two spatial scales. At the local scale, we quantified additive diversity components in 238 sampling units, and at the regional scale in five vegetation types. Total observed regional diversity (γ) was partitioned into its additive components: within sampling units (α1), among sampling units (βl) and among vegetation types (β2). We used the same approach to compare common and infrequent spider species and to compare sampling methods. A total of 1565 adult spiders and 72 identifiable juveniles, including 193 morphospecies from 36 familie.
Amyloid-β precursor protein modulates the sorting of testican-1 and contributes to its accumulation in brain tissue and cerebrospinal fluid from patients with Alzheimer disease
(Lippincott Williams and Wilkins, 2016-01-01) Ferrer, Isidre Sidre
The mechanisms leading to amyloid-β (Aβ) accumulation in sporadic Alzheimer disease (AD) are unknown but both increased production or impaired clearance likely contribute to aggregation. To understand the potential roles of the extracellular matrix proteoglycan Testican-1 in the pathophysiology of AD, we used samples from AD patients and controls and an in vitro approach. Protein expression analysis showed increased levels of Testican-1 in frontal and temporal cortex of AD patients; histological analysis showed that Testican-1 accumulates and co-aggregates with Aβ plaques in the frontal, temporal and entorhinal cortices of AD patients. Proteomic analysis identified 10 fragments of Testican-1 in cerebrospinal fluid (CSF) from AD patients. HEK293T cells expressing human wild type or mutant Aβ precursor protein (APP) were transfected with Testican-1. The co-expression of both proteins modified the sorting of Testican-1 into the endocytic pathway leading to its transient accumulation in Golgi, which seemed to affect APP processing, as indicated by reduced Aβ40 and Aβ42 levels in APP mutant cells. In conclusion, patient data reflect a clearance impairment that may favor Aβ accumulation in AD brains and our in vitro model supports the notion that the interaction between APP and Testican-1 may be a key step in the production and aggregation of Aβ species. © 2016 Oxford University Press OR American Association of Neuropathologists.
Analytical optimal pulse shapes obtained with the aid of genetic algorithms
(American Institute of Physics Inc., 2015-09-28) Reyes, Andrés
We propose a methodology to design optimal pulses for achieving quantum optimal control on molecular systems. Our approach constrains pulse shapes to linear combinations of a fixed number of experimentally relevant pulse functions. Quantum optimal control is obtained by maximizing a multi-target fitness function using genetic algorithms. As a first application of the methodology, we generated an optimal pulse that successfully maximized the yield on a selected dissociation channel of a diatomic molecule. Our pulse is obtained as a linear combination of linearly chirped pulse functions. Data recorded along the evolution of the genetic algorithm contained important information regarding the interplay between radiative and diabatic processes. We performed a principal component analysis on these data to retrieve the most relevant processes along the optimal path. Our proposed methodology could be useful for performing quantum optimal control on more complex systems by employing a wider variety of pulse shape functions. © 2015 AIP Publishing LLC.
AngiomiRs: Potential Biomarkers of Pregnancy's Vascular Pathologies
(Hindawi Publishing Corporation, 2015-01-01) Forero, Jose Vicente Forero
In recent years, microRNAs (miRNAs) have been the focus of research for their role in posttranscriptional regulation and as potential biomarkers of risk for disease development. Their identification in specific physiological processes, like angiogenesis, a key pathway in placental vascular development in pregnancy, suggests an important role of miRNAs that regulate angiogenesis (angiomiRs). Many complications of pregnancy have in common placental vascular alterations, involving an imbalance in the angiogenesis process in the development of conditions such as preeclampsia, intrauterine growth restriction, and gestational diabetes, complications with the highest rates of morbimortality in pregnancy. Many studies have identified angiomiRs with differential expression profiles in each of these diseases; however, this evidence requires further studies focused on evaluating their potential as biomarkers of risk for the angiomiRs detected, to establish correlations between placental tissue and serum/plasma expression profiles. Therefore, the objective of this review is to highlight the best angiomiRs detected in placental tissue and serum/plasma in each of these three pathologies to show the current data available for potential biomarkers and to propose future research strategies on this topic. © 2015 Laura María Rodríguez Santa et al.
Caracterización fitoquímica de una fracción de biflavonoides de garcinia madruno: su inhibición de la oxidación de ldl humana y su mecanismo de estabilización de especies radicalarias
(Universidad de Antioquia, 2009-09-22) Osorio D., Edison
A una fracción biflavonoide (FB) caracterizada fitoquímicamente de Garcinia madruno (Clusiaceae), se le evalúa su potencial inhibitorio de la oxidación de LDL y su capacidad estabilizadora de especies radicalarias, correlacionando dichas actividades con su contenido en biflavonoides. Los biflavonoides morelloflavona, volkensiflavona y amentoflavona se identifican a partir de la FB. El extracto que contiene la FB (extracto AcOEt) se determina como el principal factor involucrado en la actividad estabilizadora de radicales libres de esta especie vegetal, obteniendo la actividad estabilizadora del radical DPPH• a una concentración de 4,50 µg/mL. La peroxidación inducida con CuSO4 de las lipoproteínas de baja densidad, se reduce significativamente en presencia de FB (CE50 = 11,85 µg/mL). El biflavonoide morelloflavona se determina como el principal responsable de la protección ejercida por la FB frente a la actividad estabilizadora de radicales libres y la peroxidación lipídica, aunque posiblemente existan procesos de sinergismo. Estas propiedades sugieren que la FB de G. madruno es un excelente candidato para ser utilizado como antioxidante.
Classical mechanics of dipolar asymmetric top molecules in collinear static electric and nonresonant linearly polarized laser fields: energy-momentum diagrams, bifurcations and accessible configuration space
(World Scientific Publishing, 2008-02-08) Arango Mambuscay, Carlos Alberto
We study classical energy-momentum ($E$-$m$) diagrams for rotational motion of dipolar asymmetric top molecules in strong external fields. Static electric fields, nonresonant linearly polarized laser fields, and collinear combinations of the two are investigated. We treat specifically the molecules iodobenzene (a nearly prolate asymmetric top), pyridazine (nearly oblate asymmetric top), and iodopentafluorobenzene (intermediate case). The location of relative equilibria in the $E$-$m$ plane and associated bifurcations are determined by straightforward calculation, with analytical results given where possible. In cases where analytical solutions cannot be obtained, we resort to numerical solutions, while keeping a geometrical picture of the nature of the solutions to the fore. The classification we obtain of the topology of classically allowed rotor configuration space regions in the $E$-$m$ diagram is of potential use in characterization of energy eigenstates of the corresponding quantum mechanical problem.
Communication: Conditions for one-photon coherent phase control in isolated and open quantum systems.
(AIP Publishing, 2010-10-15) Arango Mambuscay, Carlos Alberto
Coherent control of observables using the phase properties of weak light that induces one-photon transitions is considered. Measurable properties are shown to be categorizable as either class A, where control is not possible, or class B, where control is possible. Using formal arguments, we show that phase control in open systems can be environmentally assisted.
Comportamiento circadiano del gasterópodo nerita scabricosta en el intermareal rocoso de isla la palma, pacífico colombiano
(INVEMAR, 2013-01-01) Cuellar Quiñones, José Luis
Behavior of the economic revenues of the artisanal fishery in Ciénaga Grande de Santa Marta and Complejo de Pajarales, Colombian Caribbean. In the period between “before” (1994-1996) and “after” (1999-2004) the hydraulic works the behavior of the economic yield of the artisanal fishery in Ciénaga Grande de Santa Marta and Complejo de Pajarales through the commonly used in the study area Fishing Economic Units (FEU), such as atarraya, trasmallo and boliche, was evaluated. Significant differences of the economic yield by type of FEU were observed spatially and temporarily, being atarraya and boliche the FEU that presented differences between stations and years, while trasmallo presented only temporal differences. The above is a product of the biophysical changes that suffered the lagoon system due to the different human interventions. It not only caused income changes, but also a major pressure on the lagoon system induced by the fishermen, willing to improve their socioeconomic wellbeing.
Cost-Effectiveness of the Quantification of Enzymatic Activity in Leukocytes in Comparison to Its Nonrealization for a Rare Disease in Latin America: The Case of Mucopolysaccharidosis Type II in Colombia
(Elsevier Inc., 2016-12-01) Parody Rua, Elizabeth
Background: Mucopolysaccharidosis (MPS) type II is produced by a deficiency of iduronate-2-sulfatase (I2S). The quantification of the enzyme activity in leukocytes is used as diagnostic confirmation of MPS. Objective: To determinate the cost-effectiveness of the measurement of I2S enzyme activity in leukocytes compared with not carrying out the enzyme activity measurement for diagnostic confirmation of MPS II from the perspective of the Colombian health system. Methods: A cost-effectiveness analysis was conducted on the basis of a decision tree model. The measure of effectiveness was the correct diagnosis of cases of MPS II. The costs of I2S enzymatic quantification in leukocytes, consultation with a geneticist and with other specialists, and costs of diagnostic procedures were included. The time horizon was less than 1 year. A probabilistic sensitivity analysis was performed using Monte-Carlo simulation with 10,000 iterations. Results: The incremental cost was -US $43,145 with an incremental effectiveness of 42 cases. The probabilistic sensitivity analysis confirms the results of basal data, in which the quantification of I2S enzyme activity was less costly and more effective than the alternative. Conclusions: The quantification of I2S enzymatic activity is a dominant technology for the diagnostic confirmation of MPS II, compared with not making the quantification, from the perspective of the Colombian health system. © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR).
Cost–Utility Analysis of Magnetic Resonance Imaging Management of Patients with Acute Ischemic Stroke in a Spanish Hospital
(Springer Healthcare, 2015-06-19) Dávalos, Antoni Davalos
Introduction: Stroke has a high rate of long-term disability and mortality and therefore has a significant economic impact. The objective of this study was to determine from a social perspective, the cost–utility of magnetic resonance imaging (MRI) compared to computed tomography (CT) as the first imaging test in acute ischemic stroke (AIS). Methods: A cost–utility analysis of MRI compared to CT as the first imaging test in AIS was performed. Economic evaluation data were obtained from a prospective study of patients with AIS ≤12 h from onset in one Spanish hospital. The measure of effectiveness was quality-adjusted life-years (QALYs) calculated from utilities of the modified Rankin Scale. Both hospital and post-discharge expenses were included in the costs. The incremental cost-effectiveness ratio (ICER) was calculated and sensitivity analysis was carried out. The costs were expressed in Euros at the 2004 exchange rate. Results: A total of 130 patients were analyzed. The first imaging test was CT in 87 patients and MRI in 43 patients. Baseline variables were similar in the two groups. The mean direct cost was €5830.63 for the CT group and €5692.95 for the MRI group (P = not significant). The ICER was €11,868.97/QALY. The results were sensitive when the indirect costs were included in the analysis. Conclusion: Total direct costs and QALYs were lower in the MRI group; however, this difference was not statistically significant. MRI was shown to be a cost-effective strategy for the first imaging test in AIS in 22% of the iterations according to the efficiency threshold in Spain. © 2015, The Author(s).
Coste de la incapacidad temporal debida a enfermedades musculoesqueléticas en España
(Elsevier, 2014-03-01) Parody, Elizabeth
Estimar el coste anual de la incapacidad temporal (IT) ocasionada por las enfermedades musculoesqueléticas (EME) en España y su variabilidad entre comunidades autónomas (CC. AA.) y entidades pagadoras.
Description of the nest, eggs, and nestling of Rufous-bellied Bush-Tyrants ( Myiotheretes fuscorufus )
(The Wilson Ornithological Society, 2015-01-01) Londoño, Gustavo Adolfo
The Myiotheretes bush-tyrants are a small clade of Neotropical flycatchers (family: Tyrannidae) localized to narrow elevational strips in the Andes Mountains. Here, we describe the first reported nest of Rufous-bellied Bush-Tyrants (Myiotheretes fuscorufus). It was a large cup nest lined with Usnea lichen and elevated on a sheltered rock ledge behind a flowering Puya bromeliad at 2,985 m asl in the buffer zone of Manu National Park, Peru. We provide a near-complete history of the nest from eggs through fledging, and compare data with previous nesting reports for other Myiotheretes species.
Enfoque diagnóstico molecular utilizando secuenciación exómica en las distrofias musculares cintura-cadera
(Universidad Nacional de Colombia, 2016-01-01) Lois, Sergio
Background. Limb-girdle muscular dystrophy type 1B has a dominant autosomal inheritance pattern and is caused by a mutation in the LMNA gene. This disease has a major neuromuscular and cardiac compromise; furthermore, it belongs to the limb-girdle muscular dystrophies. Objective. To make a clinical and molecular confirmatory diagnosis in a patient with proximal muscular weakness and cardiac symptoms using whole exome sequencing. Materials and Methods. This is the case of a 57 year old patient with a slowly progressive proximal muscular weakness and cardiac compromise; furthermore, the patient has many relatives with the same clinical history. Whole exome sequencing with Sanger confirmation and bioinformatics analysis was performed on the found mutation.
Erratum: “Conditions for one-photon coherent phase control in isolated and open quantum systems”
(2010-02-07) Brumer, Paul
Coherent control of observables using the phase properties of weak light that induces one-photon transitions is considered. Measurable properties are shown to be categorizable as either class A, where control is not possible, or class B, where control is possible. Using formal arguments, we show that phase control in open systems can be environmentally assisted.
False sugar sequence phenomenon and structural analysis of alpha-hederin and hederacoside c through electrospray ionization and multi-stage tandem mass spectrometry
(Universidad de Antioquia, 2011-01-01) Montoya, Guillermo
Saponins are glycosides regularly found in plants, and they are frequently analyzed by means of electrospray ion sources and tandem mass spectrometry (ESI/MSn), not only to obtain an overall molecular weight through the high sensitivity of mass spectrometry but also to obtain their structural information. The use of modern analytic techniques (such as ESI/MSn) aids the discovery and quality control assessment of new molecules found in botanicals; however, some rearrangements have been described for oligosaccharides that produce an incorrect elucidation of the molecules. For the first time, evidence for an internal sugar loss on the protonated fragmentation of a-hederin has been reported. This phenomenon can be avoided by using alkali metal ion adducts, such as lithium and sodium cations, to confirm the real sugar sequence when a structural identification is performed. In this study, the structural characterization of alpha-hederin and hederacoside C is conducted by comparing positive and negative modes. Different fragmentation patterns occur, and such patterns are useful in the structural analysis of saponins when they are present on different matrixes.
First nesting account and breeding biology of "gould's Inca" (Coeligena torquata omissa) in Manu National Park, Peru
(Wilson Ornithological Society, 2016-09-03) Londoño, Gustavo Adolfo
We present the first detailed nesting biology information for the highland Andean hummingbird Gould's Inca (Coeligena torquata omissa) at 2,200-3,000 m in Manu National Park, SE Peru. We found nine mossy cup-shaped nests lined with red fern scales containing nestlings or 1-2 synchronously hatching eggs. We obtained 17 days of internal nest temperatures from one nest, which exhibited wide circadian variation (range = 14.9-36.2 °C). We show that C. t. omissa meets the challenges of life and incubation at high altitudes by undertaking numerous (20.3 ± 0.4 trips/morning, range = 14-27) and short morning off-bouts (5.2 ± 0.2 min, range = 1-24 min). In the morning, the focal bird warmed the nest 1.7 times faster than in the afternoon where incubation bouts are long (17.8 ± 0.6 min, range = 4-56) and less frequent (10.2 ± 0.3 trips/afternoon). Incubation off-bout frequency and durations were not influenced by external temperature, suggesting strong nest insulation. On-bout durations increased with external temperature most strongly in the cold mornings. Short off-bouts and long on-bouts yielded high attentiveness (70.2%). One nestling fledged after 23 days. The eggs measured 15.2 ± 0.4 mm by 9.3 ± 0.3 mm and weighed 0.75 ± 0.03 g (n = 12). The small mossy cup nest was 81.9 ± 5.9 mm by 75.8 ± 4.4 mm wide and 73.1 ± 6.7 mm high. The inner cup was 45.7 ± 3.0 mm long by 45.6 ± 4.1 mm wide and 30.9 ± 2.5 mm deep (n = 8). Compared to C. t. torquata, we found a smaller egg width, higher nest placement and different nest substrate, but confirmed similarities in many aspects of nesting strategies.

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Examinando Nuevo conocimiento - NAT por Materia "Biología"