2,037 research outputs found
Get it from the Source: Identifying Library Resources and Software Used in Faculty Research
Libraries and Information Technology departments aim to support the educational and research needs of students, researchers, and faculty members. Close matches between the resources those departments provide and the resources the institutionâs community members actually use highlight the value of the departments, demonstrate fiscally responsibility, and show attentiveness to the communityâs needs. Traditionally, libraries rely on usage statistics to guide collection development decisions, but usage statistics can only imply value. Identifying a resource by name in a publication demonstrates the value of that resource more clearly. This pilot project examined the full-text of articles published in 2016-2017 by faculty members at a mid-sized, special-focus institution to answer the questions âDo faculty members have university-provided access to the research tools they need to publish?â and âIf not, where are they getting them?â Using a custom database, the presenters indexed every publication by author, publication, resources used, availability of the identified resources, and more. This pilot study can be adapted to projects at other institutions, allowing them to gain a better understanding of the strengths and weaknesses of their own institutionâs offerings. In addition, they will be able to identify ways to use that data to negotiate for additional resources, inform strategic partnerships, and facilitate open discussions with the institutionâs community
A Revised Design for Microarray Experiments to Account for Experimental Noise and Uncertainty of Probe Response
Background
Although microarrays are analysis tools in biomedical research, they are known to yield noisy output that usually requires experimental confirmation. To tackle this problem, many studies have developed rules for optimizing probe design and devised complex statistical tools to analyze the output. However, less emphasis has been placed on systematically identifying the noise component as part of the experimental procedure. One source of noise is the variance in probe binding, which can be assessed by replicating array probes. The second source is poor probe performance, which can be assessed by calibrating the array based on a dilution series of target molecules. Using model experiments for copy number variation and gene expression measurements, we investigate here a revised design for microarray experiments that addresses both of these sources of variance.
Results
Two custom arrays were used to evaluate the revised design: one based on 25 mer probes from an Affymetrix design and the other based on 60 mer probes from an Agilent design. To assess experimental variance in probe binding, all probes were replicated ten times. To assess probe performance, the probes were calibrated using a dilution series of target molecules and the signal response was fitted to an adsorption model. We found that significant variance of the signal could be controlled by averaging across probes and removing probes that are nonresponsive or poorly responsive in the calibration experiment. Taking this into account, one can obtain a more reliable signal with the added option of obtaining absolute rather than relative measurements.
Conclusion
The assessment of technical variance within the experiments, combined with the calibration of probes allows to remove poorly responding probes and yields more reliable signals for the remaining ones. Once an array is properly calibrated, absolute quantification of signals becomes straight forward, alleviating the need for normalization and reference hybridizations
Discrimination of Potent Inhibitors of Toxoplasma gondii Enoyl-Acyl Carrier Protein Reductase by a Thermal Shift Assay
Many microbial pathogens rely on a type II fatty acid synthesis (FASII) pathway that is distinct from the type I pathway found in humans. Enoyl-acyl carrier protein reductase (ENR) is an essential FASII pathway enzyme and the target of a number of antimicrobial drug discovery efforts. The biocide triclosan is established as a potent inhibitor of ENR and has been the starting point for medicinal chemistry studies. We evaluated a series of triclosan analogues for their ability to inhibit the growth of Toxoplasma gondii, a pervasive human pathogen, and its ENR enzyme (TgENR). Several compounds that inhibited TgENR at low nanomolar concentrations were identified but could not be further differentiated because of the limited dynamic range of the TgENR activity assay. Thus, we adapted a thermal shift assay (TSA) to directly measure the dissociation constant (Kd) of the most potent inhibitors identified in this study as well as inhibitors from previous studies. Furthermore, the TSA allowed us to determine the mode of action of these compounds in the presence of the reduced nicotinamide adenine dinucleotide (NADH) or nicotinamide adenine dinucleotide (NAD+) cofactor. We found that all of the inhibitors bind to a TgENRâNAD+ complex but that they differed in their dependence on NAD+ concentration. Ultimately, we were able to identify compounds that bind to the TgENRâNAD+ complex in the low femtomolar range. This shows how TSA data combined with enzyme inhibition, parasite growth inhibition data, and ADMET predictions allow for better discrimination between potent ENR inhibitors for the future development of medicine
Aluminium content of spanish infant formula
Aluminium toxicity has been relatively well documented in infants with impaired renal
function and premature neonates.
The aims of this study were to analyse the concentration of aluminium in the majority of
infant formulae sold commercially in Spain, to determine the influence of aluminium
content in the tap water in reconstituted powder formulae and to estimate the theoretical
toxic aluminium intake in comparison with the PTWI, and lastly, to discuss the possible
interactions of certain essential trace elements added to formulation with aluminium
according to type or main protein based infant formula.
A total of 82 different infant formulae from 9 different manufacturers were studied.
Sample digestion was simulated in a closed acid-decomposition microwave system.
Aluminium concentration was determined by atomic absorption spectrophotometry with
graphite furnace.
In general, the infant formulae studied provide an aluminium level higher than that found
in human milk, especially in the case of soya, preterm or hydrolysed casein-based
formulae.
Standard formulae provide lower aluminium intakes amounting to about 4 % PTWI.
Specialised and preterm formulae result in moderate intake (11 â 12 % and 8 â 10 %
PTWI, respectively). Soya formulae contribute the highest intake (15 % PTWI).
Aluminium exposure from drinking water used for powder formula reconstitution is not
considered a clear potential risk.
In accordance with the present state of knowledge about aluminium toxicity, it seems
prudent to call for continued efforts to standardise routine quality control and reduce
aluminium levels in infant formula as well as to keep the aluminium concentration under
300 g l-1 for all infant formulae, most specifically those formulae for premature and low
birth neonates
Cold streams in early massive hot haloes as the main mode of galaxy formation
The massive galaxies in the young universe, ten billion years ago, formed
stars at surprising intensities. Although this is commonly attributed to
violent mergers, the properties of many of these galaxies are incompatible with
such events, showing gas-rich, clumpy, extended rotating disks not dominated by
spheroids (Genzel et al. 2006, 2008). Cosmological simulations and clustering
theory are used to explore how these galaxies acquired their gas. Here we
report that they are stream-fed galaxies, formed from steady, narrow, cold gas
streams that penetrate the shock-heated media of massive dark matter haloes
(Dekel & Birnboim 2006; Keres et al. 2005). A comparison with the observed
abundance of star-forming galaxies implies that most of the input gas must
rapidly convert to stars. One-third of the stream mass is in gas clumps leading
to mergers of mass ratio greater than 1:10, and the rest is in smoother flows.
With a merger duy cycle of 0.1, three-quarters of the galaxies forming stars at
a given rate are fed by smooth streams. The rarer, submillimetre galaxies that
form stars even more intensely are largely merger-induced starbursts. Unlike
destructive mergers, the streams are likely to keep the rotating disk
configuration intact, although turbulent and broken into giant star-forming
clumps that merge into a central spheroid (Noguchi 1999; Genzel et al. 2008,
Elmegreen, Bournaud & Elmegreen 2008, Dekel, Sari & Ceverino 2009). This
stream-driven scenario for the formation of disks and spheroids is an
alternative to the merger picture.Comment: Improved version, 25 pages, 13 figures, Letter to Nature with
Supplementary Informatio
The Impact of a Dedicated Research Education Month for Anesthesiology Residents
An educational intervention was implemented at the University of Michigan starting in 2008, in which anesthesiology interns complete a dedicated month-long didactic rotation in evidence-based medicine (EBM) and research methodology. We sought to assess its utility. Scores on a validated EBM test before and after the rotation were compared and assessed for significance of improvement. A survey was also given to gauge satisfaction with the quality of the rotation and self-reported improvement in understanding of EBM topics. Fourteen consecutive interns completed the research rotation during the study period. One hundred percent completed both the pre- and postrotation test. The mean pretest score was 7.78 ± 2.46 (median = 7.5, 0â15 scale, and interquartile range 7.0â10.0) and the mean posttest score was 10.00 ± 2.35 (median = 9.5, interquartile range 8.0â12.3), which represented a statistically significant increase (P=0.011, Wilcoxon signed-rank test). All fourteen of the residents âagreedâ or âstrongly agreedâ that they would recommend the course to future interns and that the course increased their ability to critically review the literature. Our findings demonstrate that this can be an effective means of improving understanding of EBM topics and anesthesiology research
The ALMA-ALPINE [CII] survey: Kennicutt-Schmidt relation in four massive main-sequence galaxies at <i>z</i> ⌠4.5
Aims. The Kennicutt-Schmidt (KS) relation between the gas and the star formation rate (SFR) surface density (ÎŁâ
ââ
ÎŁ) is essential to understand star formation processes in galaxies. To date, it has been measured up to z ⌠2.5 in main-sequence galaxies. In this Letter our aim is to put constraints at zââŒâ4.5 using a sample of four massive main-sequence galaxies observed by ALMA at high resolution.
Methods. We obtained âŒ0.3âł-resolution [CII] and continuum maps of our objects, which we then converted into gas and obscured SFR surface density maps. In addition, we produced unobscured SFR surface density maps by convolving Hubble ancillary data in the rest-frame UV. We then derived the average ÎŁ in various ÎŁ bins, and estimated the uncertainties using a Monte Carlo sampling.
Results. Our galaxy sample follows the KS relation measured in main-sequence galaxies at lower redshift, and is slightly lower than the predictions from simulations. Our data points probe the high end both in terms of ÎŁ and ÎŁ, and gas depletion timescales (285â843 Myr) remain similar to z ⌠2 objects. However, three of our objects are clearly morphologically disturbed, and we could have expected shorter gas depletion timescales (âČ100 Myr) similar to merger-driven starbursts at lower redshifts. This suggests that the mechanisms triggering starbursts at high redshift may be different than in the low- and intermediate-z Universe
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