1,576 research outputs found
Measurements design and phenomena discrimination
The construction of measurements suitable for discriminating signal
components produced by phenomena of different types is considered. The required
measurements should be capable of cancelling out those signal components which
are to be ignored when focusing on a phenomenon of interest. Under the
hypothesis that the subspaces hosting the signal components produced by each
phenomenon are complementary, their discrimination is accomplished by
measurements giving rise to the appropriate oblique projector operator. The
subspace onto which the operator should project is selected by nonlinear
techniques in line with adaptive pursuit strategies
Decay of Quantum Accelerator Modes
Experimentally observable Quantum Accelerator Modes are used as a test case
for the study of some general aspects of quantum decay from classical stable
islands immersed in a chaotic sea. The modes are shown to correspond to
metastable states, analogous to the Wannier-Stark resonances. Different regimes
of tunneling, marked by different quantitative dependence of the lifetimes on
1/hbar, are identified, depending on the resolution of KAM substructures that
is achieved on the scale of hbar. The theory of Resonance Assisted Tunneling
introduced by Brodier, Schlagheck, and Ullmo [9], is revisited, and found to
well describe decay whenever applicable.Comment: 16 pages, 11 encapsulated postscript figures (figures with a better
resolution are available upon request to the authors); added reference for
section
Functional Approach to Quantum Decoherence and the Classical Final Limit
For a wide set of quantum systems it is demonstrated that the quantum regime
can be considered as the transient phase while the final classical statistical
regime is a permanent state. A basis where exact matrix decoherence appears for
these final states is found. The relation with the decoherence of histories
formalism is studied. A set of final intrinsically consistent histories is
found.Comment: 20 pages. Phys. Rev A in press 200
Criteria for effective design, construction, and gene knockdown by shRNA vectors
BACKGROUND: RNA interference (RNAi) technology is a powerful methodology recently developed for the specific knockdown of targeted genes. RNAi is most commonly achieved either transiently by transfection of small interfering (si) RNA oligonucleotides, or stably using short hairpin (sh) RNA expressed from a DNA vector or virus. Much controversy has surrounded the development of rules for the design of effective siRNA oligonucleotides; and whether these rules apply to shRNA is not well characterized. RESULTS: To determine whether published algorithms for siRNA oligonucleotide design apply to shRNA, we constructed 27 shRNAs from 11 human genes expressed stably using retroviral vectors. We demonstrate an efficient method for preparing wild-type and mutant control shRNA vectors simultaneously using oligonucleotide hybrids. We show that sequencing through shRNA vectors can be problematic due to the intrinsic secondary structure of the hairpin, and we determine a strategy for effective sequencing by using a combination of modified BigDye chemistries and DNA relaxing agents. The efficacy of knockdown for the 27 shRNA vectors was evaluated against six published algorithms for siRNA oligonucleotide design. Our results show that none of the scoring algorithms can explain a significant percentage of variance in shRNA knockdown efficacy as assessed by linear regression analysis or ROC curve analysis. Application of a modification based on the stability of the 6 central bases of each shRNA provides fair-to-good predictions of knockdown efficacy for three of the algorithms. Analysis of an independent set of data from 38 shRNAs pooled from previous publications confirms these findings. CONCLUSION: The use of mixed oligonucleotide pairs provides a time and cost efficient method of producing wild type and mutant control shRNA vectors. The addition to sequencing reactions of a combination of mixed dITP/dGTP chemistries and DNA relaxing agents enables read through the intrinsic secondary structure of problematic shRNA vectors. Six published algorithms for siRNA oligonucleotide design that were tested in this study show little or no efficacy at predicting shRNA knockdown outcome. However, application of a modification based on the central shRNA stability should provide a useful improvement to the design of effective shRNA vectors
Brain activation during dual-task processing is associated with cardiorespiratory fitness and performance in older adults
Citation: Wong, C. N., Chaddock-Heyman, L., Voss, M. W., Burzynska, A. Z., Basak, C., Erickson, K. I., . . . Kramer, A. F. (2015). Brain activation during dual-task processing is associated with cardiorespiratory fitness and performance in older adults. Frontiers in Aging Neuroscience, 7, 10. doi:10.3389/fnagi.2015.00154Higher cardiorespiratory fitness is associated with better cognitive performance and enhanced brain activation. Yet, the extent to which cardiorespiratory fitness-related brain activation is associated with better cognitive performance is not well understood. In this cross-sectional study, we examined whether the association between cardiorespiratory fitness and executive function was mediated by greater prefrontal cortex activation in healthy older adults. Brain activation was measured during dual-task performance with functional magnetic resonance imaging in a sample of 128 healthy older adults (59-80 years). Higher cardiorespiratory fitness was associated with greater activation during dual-task processing in several brain areas including the anterior cingulate and supplementary motor cortex (ACC/SMA), thalamus and basal ganglia, right motor/somatosensory cortex and middle frontal gyrus, and left somatosensory cortex, controlling for age, sex, education, and gray matter volume. Of these regions, greater ACC/SMA activation mediated the association between cardiorespiratory fitness and dual-task performance. We provide novel evidence that cardiorespiratory fitness may support cognitive performance by facilitating brain activation in a core region critical for executive function
AIDS virusâspecific CD8+ T lymphocytes against an immunodominant cryptic epitope select for viral escape
Cryptic major histocompatibility complex class I epitopes have been detected in several pathogens, but their importance in the immune response to AIDS viruses remains unknown. Here, we show that Mamu-B*17+ simian immunodeficiency virus (SIV)mac239-infected rhesus macaques that spontaneously controlled viral replication consistently made strong CD8+ T lymphocyte (CD8-TL) responses against a cryptic epitope, RHLAFKCLW (cRW9). Importantly, cRW9-specific CD8-TL selected for viral variation in vivo and effectively suppressed SIV replication in vitro, suggesting that they might play a key role in the SIV-specific response. The discovery of an immunodominant CD8-TL response in elite controller macaques against a cryptic epitope suggests that the AIDS virusâspecific cellular immune response is likely far more complex than is generally assumed
Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution
BackgroundControlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure.ObjectivesThe primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures.MethodsWe conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or PolotitlĂĄn (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography.ResultsMexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 ÎŒm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03).ConclusionsChronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure
PenQuest Volume 2, Number 1
Table of Contents for this Volume:
Untitled by Janet Collins
Untitled by Judy Gozdur
Last Hour of Light by Susan Reed
Untitled by Judy Godzur
Untitled by Rick Wagner
Untitled by Carol Groover
Untitled by R. Wagner
Only in the Portico by Linda Banicki
Untitled by Helen Hagadorn
Private Place, Pubic Place by David Reed
Untitled by Tammy Hutchinson
Untitled by Tammy Hutchinson
Madison Knights by Susan Reed
Untitled by Sissy Crabtree
The Price by Sandra Coleman
Untitled by Ann Harrington
Invasion of Privacy by Mark Touchton
Untitled by Bruce Warner
Untitled by Tom Schifanella
Untitled by Tammy Hutchinson
Bloodwork by Laura Jo Last
Untitled by David Whitsett
Burial Instructions by Bill Slaughter
Untitled by S. Trevett
PenQuest Interview: Joe Haldeman by David Reed
Her Name Came from the Sea by Richard L. Ewart
Untitled by V. Williams
In the Woodshed by R. E. Mallery
Untitled by Modesta Matthews
Untitled by David Olson
Illumination by E. Allen Tilley
Untitled by Joseph Avanzini
Everywoman by Laura Jo Last
Untitled by Beth Goeckel
Believe Me by Donna Kaluzniak
Untitled by Judy Gozdur
Untitled by Judy Gozdur
Unicorn by David Reed
Untitled by Susan Reed
untitled by Paul Cramer
Unititled by Lucinda Halsema
The Violin by Richard L. Ewart
Untitled by Maria Barry
Untitled by Roger Whitt Jr.
Haiku by Lori Nasrallah
Rhymerâs Revolt by R. E. Mallery
Untitled by Valerie William
Detection of physiological deterioration by the SNAP40 wearable device compared to standard monitoring devices in the emergency department::the SNAP40-ED study
Abstract Background In recent years, there has been increasing focus on the earlier detection of deterioration in the clinical condition of hospital patients with the aim of instigating earlier treatment to reverse this deterioration and prevent adverse outcomes. This is especially important in the ED, a dynamic environment with large volumes of undifferentiated patients, which carries inherent patient risk. SNAP40 is an innovative medical-grade device that can be worn on the upper arm that continuously monitors patientsâ vital signs including relative changes in systolic blood pressure, respiratory rate, heart rate, movement, blood oxygen saturation and temperature. It uses automated risk analysis to potentially allow clinical staff to easily and quickly identify high-risk patients. The aim of this study is to investigate whether the SNAP40 device is able to identify deterioration in the vital sign physiology of an ED patient earlier than current standard monitoring and observation charting techniques. Methods/design Single centre, teaching hospital ED open label, prospective, observational cohort study recruiting 250 high acuity participants aged 16Â years or over presenting to the ED. Participants will be approached and enrolled in the ED and after consent will have the SNAP40 wearable monitoring device attached which will be used alongside standard care monitoring. Participants will be observed throughout their time in the ED. Any SNAP40 device alarm, standard monitoring alarms or standard practice vital sign observations indicating a deterioration in a patientâs vital sign physiology (defined as an increase in NEWS score) will be recorded. Primary outcome is time to detection of deterioration. Secondary outcomes include staff time spent performing observations and responding to standard monitoring alarms, clinical escalation of care when deterioration is detected and participants and staff rating of experience of both SNAP40 and current monitoring. Discussion The SNAP40-ED study aims to recruit 250 patients. It will be the first study to compare the ability of a novel ambulatory monitoring device to detect deterioration compared to standard care in the ED. It may allow the earlier detection of deterioration in the clinical condition of ED patients and therefore earlier treatment to reverse this deterioration and prevent adverse outcomes. Trial registration NCT03179267 ClinicalTrials.gov. Registered on June 17, 201
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