1,525 research outputs found
A Validated Reversed-Phase HPLC Method for the Determination of Atorvastatin Calcium in Tablets
A Reversed-Phase Liquid Chromatographic (RP-LC) assay method was developed for the quantitative determination of atorvastatin calcium in the presence of its degradation products. The assay involved an isocratic elution of atorvastatin calcium in a LiChroCARTR 250*4 mm HPLC Cartridge LiChrospherR 100 RP-18 (5 μm) column using a mobile phase consisting of 0.1% acetic acid solution: acetonitrile (45:55, v/v), pH = 3.8. The flow rate was 0.8 mL/min and the analytes monitored at 246 nm. The assay method was found to be linear from 8.13 to 23.77 μg/mL. All the validation parameters were within the acceptance range. The developed method was successfully applied to estimate the amount of atorvastatin calcium in tablets.Fil: Simionato, Laura Daniela. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; ArgentinaFil: Ferello, L.. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; ArgentinaFil: Stamer. S.. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; ArgentinaFil: Repetto, M. F.. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; ArgentinaFil: Zubata, P. D.. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; ArgentinaFil: Segall, Adriana Ines. Universidad de Buenos Aires. Facultad de Farmacia y BioquÃmica. Departamento de TecnologÃa Farmacéutica; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin
From sensorimotor dependencies to perceptual practices: making enactivism social
Proponents of enactivism should be interested in exploring what notion of action best captures the type of action-perception link that the view proposes, such that it covers all the aspects in which our doings constitute and are constituted by our perceiving. This article proposes and defends the thesis that the notion of sensorimotor dependencies is insufficient to account for the reality of human perception, and that the central enactive notion should be that of perceptual practices. Sensorimotor enactivism is insufficient because it has no traction on socially dependent perceptions, which are essential to the role and significance of perception in our lives. Since the social dimension is a central desideratum in a theory of human perception, enactivism needs a notion that accounts for such an aspect. This article sketches the main features of the Wittgenstein-inspired notion of perceptual practices as the central notion to understand perception. Perception, I claim, is properly understood as woven into a type of social practices that includes food, dance, dress, music, etc. More specifically, perceptual practices are the enactment of culturally structured, normatively rich techniques of commerce of meaningful multi- and inter-modal perceptible material. I argue that perceptual practices explain three central features of socially dependent perception: attentional focus, aspects’ saliency, and modal-specific harmony-like relations
Spermidine biases the resolution of Holliday junctions by phage λ integrase
Holliday junctions are a central intermediate in diverse pathways of DNA repair and recombination. The isomerization of a junction determines the directionality of the recombination event. Previous studies have shown that the identity of the central sequence of the junction may favor one of the two isomers, in turn controlling the direction of the pathway. Here we demonstrate that, in the absence of DNA sequence-mediated isomer preference, polycations are the major contributor to biasing strand cleavage during junction resolution. In the case of wild-type phage λ excision junctions, spermidine plays the dominant role in controlling the isomerization state of the junction and increases the rate of junction resolution. Spermidine also counteracts the sequence-imposed bias on resolution. The spermidine-induced bias is seen equally on supercoiled and linear excisive recombination junction intermediates, and thus is not just an artefact of in vitro recombination conditions. The contribution of spermidine requires the presence of accessory factors, and results in the repositioning of Int's core-binding domains on junctions, perhaps due to DNA-spermidine–protein interactions, or by influencing DNA conformation in the core region. Our results lead us to propose that spermidine together with accessory factors promotes the formation of the second junction isomer. We propose that this rearrangement triggers the activation of the second pair of Int active sites necessary to resolve Holliday junctions during phage λ Int-mediated recombination
Toward Citizen Centricity: Leveraging the Citizens Academy to Foster Inclusive, Sustainable, and Generative Civic Engagement in Midland, MI
This service learning project aims to utilize positive psychology research to foster inclusive, sustainable, and generative civic engagement among residents of Midland, Michigan. We conceptualize civic engagement as an outgrowth of social capital, and we leverage the constructs of mattering, fairness, belonging, and bridging to offer positive interventions aimed at increasing Midland’s social capital. Specifically, we propose several changes to evolve the city government’s existing educational civic leadership program called the Citizens Academy. First, we suggest adjusting the academy’s recruitment process to expand access and inclusion by increasing the number and diversity of participants. Second, we introduce a more participatory and citizen-centered approach to the program content that builds on Midland’s four strategic pillars as a guiding framework. We offer four positive psychology-based exercises to be interwoven into the Citizens Academy curriculum: Strengths and Values, Community Exploration Guide, Citizen-to-Citizen Coaching, and Storytelling. Third, we recommend a Civic Engagement Scale as a simple tool to measure initial outcomes. It is our hope that this service learning project will serve not only as an initial catalyst for Midland’s goal of increasing civic engagement, but as a model for other cities and communities looking to utilize the science of positive psychology to effect large-scale change
Egalitarian justice and expected value
According to all-luck egalitarianism, the differential distributive effects of both brute luck, which defines the outcome of risks which are not deliberately taken, and option luck, which defines the outcome of deliberate gambles, are unjust. Exactly how to correct the effects of option luck is, however, a complex issue. This article argues that (a) option luck should be neutralized not just by correcting luck among gamblers, but among the community as a whole, because it would be unfair for gamblers as a group to be disadvantaged relative to non-gamblers by bad option luck; (b) individuals should receive the warranted expected results of their gambles, except insofar as individuals blamelessly lacked the ability to ascertain which expectations were warranted; and (c) where societal resources are insufficient to deliver expected results to gamblers, gamblers should receive a lesser distributive share which is in proportion to the expected results. Where all-luck egalitarianism is understood in this way, it allows risk-takers to impose externalities on non-risk-takers, which seems counterintuitive. This may, however, be an advantage as it provides a luck egalitarian rationale for assisting ‘negligent victims’
Cortical Thickness and Subcortical Gray Matter Reductions in Neuropsychiatric Systemic Lupus Erythematosus
Within systemic lupus erythematosus (SLE) patients can be divided into groups with and without central nervous system involvement, the latter being subcategorized as neuropsychiatric systemic lupus erythematosus (NPSLE). While a number of research groups have investigated NPSLE, there remains a lack of consistent application of this diagnostic criteria within neuroimaging studies. Previous neuroimaging research suggests that SLE patients have reduced subcortical and regional gray matter volumes when compared to controls, and that these group differences may be driven by SLE patients with neuropsychiatric symptoms. The current study sought to compare measures of cortical thickness and subcortical structure volume between NPSLE, SLE, and healthy controls. We hypothesized that patients with NPSLE (N = 21) would have thinner cortex and reduced subcortical gray matter volumes when compared to SLE (N = 16) and control subjects (N = 21). All subjects underwent MRI examinations on a 1.5 Tesla Siemens Sonata scanner. Anatomical reconstruction and segmentation were performed using the FreeSurfer image analysis suite. Cortical and subcortical volumes were extracted from FreeSurfer and analyzed for group differences, controlling for age. The NPSLE group exhibited decreased cortical thickness in clusters of the left frontal and parietal lobes as well as in the right parietal and occipital lobes compared to control subjects. Compared to the SLE group, the NPSLE group exhibited comparable thinning in clusters of the frontal and temporal lobes. Controlling for age, we found that between group effects for subcortical gray matter structures were significant for the thalamus (F = 3.06, p = .04), caudate nucleus (F = 3.19, p = .03), and putamen (F = 4.82, p = .005). These results clarify previous imaging work identifying cortical atrophy in a mixed SLE and NPSLE group, and suggest that neuroanatomical abnormalities are specific to SLE patients diagnosed with neuropsychiatric symptoms. Future work should help elucidate the underlying mechanisms underlying the emerging neurobiological profile seen in NPSLE, as well as clarify the apparent lack of overlap between cortical thinning and functional activation results and other findings pointing to increased functional activation during cognitive tasks
MSEC2006-21098 RESULTS OF CYLINDER BORE INSPECTION PROBE MEASUREMENTS
ABSTRACT A non contact optical technique for mapping the surface finish of cylinder bores has been developed, and a probe has been built for performing this mapping by scanning the surface of a cylinder with a laser beam and recording the intensity of scattered light detected as a function of position on the cylinder surface. The probe is not a surface roughness gauge. It is used primarily to distinguish the scattering signatures from different patterns of machining marks. For identical patterns of machining marks scattered light intensity is expected to be proportional to surface roughness. Measurement of a cylinder takes about 10 seconds using this probe. If an array of probes were used to inspect the cylinders of an engine block simultaneously, this technique could be used for 100% inspection of the entire surface of every cylinder of every block at the speed of an engine production line. In this paper we present data from a proof of concept experiment, describe the method of analyzing the data, and outline plans for future implementation of an inspection station on an engine block production line
Spin-dependent resonant tunneling through semimetallic ErAs quantum wells
Resonant tunneling through semimetallic ErAs quantum wells embedded in GaAs
structures with AlAs barriers was recently found to exhibit an intriguing
behavior in magnetic fields which is explained in terms of tunneling selection
rules and the spin-polarized band structure including spin-orbit coupling.Comment: 4 pages, figures supplied as self-unpacking figures.uu, uses
epsfig.sty to incorporate figures in preprin
Magnetism in Cr-doped ZnS: Density-functional theory studies
We investigated the magnetism and aggregation trends in cubic Zn1-xCrxS using
the density-functional theory calculations.We demonstrate that all studied
configurations show ground state half-metallic ferromagnetism (HMF); and Cr
impurities are energetically favorable to planar cluster into delta-doping
structures. The single-layer delta-doping structures of Zn0.75Cr0.25S and
Zn0.875Cr0.125S show ferromagnetic stabilization energies (\Delta E_AF) of
0.551 and 0.561 eV/Cr-Cr pair, respectively. The half-layer delta-doping
structure of Zn0.875Cr0.125S and double-layer delta-doping structure of
Zn0.75Cr0.25S show \Delta E_AF of 0.394 and 0.166 eV/Cr-Cr pair, respectively.
Furthermore, our studies indicate that the cubic ZnS/CrS heterostructure, one
extreme situation of the delta-doping structure, also shows ground state HMF.
The origin of HMF is discussed using a simple crystal field model. Finally, we
anticipate the potential spintronics application of Zn1-xCrxS.Comment: 13 pages, 4 figure
- …