206 research outputs found
Periodic Heart Rate Decelerations in Premature Infants
The pacemaking system of the heart is complex; a healthy heart constantly integrates and responds to extracardiac signals, resulting in highly complex heart rate patterns with a great deal of variability. In the laboratory and in some pathological or age-related states, however, dynamics can show reduced complexity that is more readily described and modeled. Reduced heart rate complexity has both clinical and dynamical significance - it may provide warning of impending illness or clues about the dynamics of the heart\u27s pacemaking system. In this paper, we describe simple and interesting heart rate dynamics that we have observed in premature human infants - reversible transitions to large-amplitude periodic oscillations - and we show that the appearance and disappearance of these periodic oscillations can be described by a simple mathematical model, a Hopf bifurcation
The Large-scale J=3-2 and J=2-1 CO Emission from M17 and its Implications for Extragalactic CO Observations
We observed a 10x20 pc region of the molecular cloud M17 in the 12CO and 13CO
J=3-2 and J=2-1 transitions to determine their global behavior and to assess
the reliability of using ratios of CO line intensities integrated over an
entire cloud to determine the physical conditions within the cloud. Both the
12CO/13CO J=2-1 and J=3-2 line ratios correlate with the 13CO integrated
intensity, with smaller line ratios observed at locations with large integrated
intensities. This correlation is likely due to variations in the column density
from one position to another within M17. The 12CO and 13CO (J=3-2/J=2-1) line
ratios show no significant variation from place to place within M17, even on
the peak of the photon-dominated region. A Large Velocity Gradient analysis of
globally averaged line ratios gives results in reasonable agreement with the
results obtained for individual lines-of-sight through the cloud, which
suggests that the typical physical conditions in a molecular cloud can be
determined using CO line ratios integrated over the entire cloud. There appears
to be a clear trend of increasing 12CO/13CO J=2-1 and J=3-2 line ratios as one
moves from Galactic molecular cloud cores to entire Galactic molecular clouds
to normal galaxies. The most likely explanation of the high line ratios for
normal galaxies is a significant contribution to the CO emission by low column
density material, such as diffuse molecular clouds or the outer envelopes of
giant molecular clouds.Comment: 26 pages, 6 figures, 2 tables. Accepted for publication in Ap
“Integrated” and “insulated” boronate-based fluorescent probes for the detection of hydrogen peroxide
Anti-Allergic Cromones Inhibit Histamine and Eicosanoid Release from Activated Human and Murine Mast Cells by Releasing Annexin A1
PMCID: PMC3601088This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Colorimetric enantioselective recognition of chiral secondary alcohols <em>via</em> hydrogen bonding to a chiral metallocene containing chemosensor
China Scholarship Council (CSC); University of Bath; Natural Science Foundation of China [21050110426]; ECUSTAn operationally simple colorimetric method for enantioselective detection of chiral secondary alcohols via hydrogen bonding interactions using a chiral ferrocene derivative is reported
Colorimetric enantioselective recognition of chiral secondary alcohols via hydrogen bonding to a chiral metallocene containing chemosensor
China Scholarship Council (CSC); University of Bath; Natural Science Foundation of China [21050110426]; ECUSTAn operationally simple colorimetric method for enantioselective detection of chiral secondary alcohols via hydrogen bonding interactions using a chiral ferrocene derivative is reported
Bolstering Confidence in Obesity Prevention and Treatment Counseling for Resident and Community Pediatricians
Objective- To assess whether equipping resident pediatricians and community pediatricians with both training and practical tools improves their perceived confidence, ease, and frequency of obesity related counseling to patients.
Methods- In 2005-2006, resident pediatricians (n = 49) and community pediatricians (n=18) received training regarding three evidence-based obesity prevention/treatment tools and responded to pre-and post-intervention questionnaires. We analyzed changes in reported mean confidence, ease, and frequency of dietary, physical activity, and weight status counseling.
Results- Baseline scores of confidence, ease, and frequency of counseling were higher in community pediatricians than residents. Mean scores increased significantly in the combined group, among residents only, and trended towards improvement in the community pediatricians following the intervention. Means for "control" questions were unchanged.
Conclusion- Training and tools for residents and community pediatricians improved their confidence, ease, and frequency of obesity-related counseling.
Practice Implications- This study demonstrates that when feasible and appropriate tools and training were provided through a simple intervention, physicians gained confidence and ease and increased their counseling frequency. The results here suggest that widespread implementation of such educational interventions for community practitioners and practitioners in training could change the way physicians counsel patients to prevent the often frustrating problem of childhood obesity. Originally published Patient Education and Counseling, Vol. 73, No. 2, Nov 200
Hydrothermal conversion of one-photon-fluorescent poly-(4-vinylpyridine) into two-photon-fluorescent carbon nanodots
A novel two-photon-fluorescent N,O-heteroatom-rich carbon nanomaterial has been synthesized and characterized. The new carbon nanoparticles were produced by hydrothermal conversion from a one-photon-fluorescent poly(4-vinylpyridine) precursor (P4VP). The carbonized particles (cP4VP dots) with nonuniform particle diameter (ranging from sub-6 to 20 nm with some aggregates up to 200 nm) exhibit strong fluorescence properties in different solvents and have also been investigated for applications in cell culture media. The cP4VP dots retain their intrinsic fluorescence in a cellular environment and exhibit an average excited-state lifetime of 2.0 ± 0.9 ns in the cell. The cP4VP dots enter HeLa cells and do not cause significant damage to outer cell membranes. They provide one-photon or two-photon fluorescent synthetic scaffolds for imaging applications and/or drug delivery
Mast Cells Express 11 beta-hydroxysteroid Dehydrogenase Type 1: A Role in Restraining Mast Cell Degranulation:a role in restraining mast cell degranulation
Mast cells are key initiators of allergic, anaphylactic and inflammatory reactions, producing mediators that affect vascular permeability, angiogenesis and fibrosis. Glucocorticoid pharmacotherapy reduces mast cell number, maturation and activation but effects at physiological levels are unknown. Within cells, glucocorticoid concentration is modulated by the 11β-hydroxysteroid dehydrogenases (11β-HSDs). Here we show expression and activity of 11β-HSD1, but not 11β-HSD2, in mouse mast cells with 11β-HSD activity only in the keto-reductase direction, regenerating active glucocorticoids (cortisol, corticosterone) from inert substrates (cortisone, 11-dehydrocorticosterone). Mast cells from 11β-HSD1-deficient mice show ultrastructural evidence of increased activation, including piecemeal degranulation and have a reduced threshold for IgG immune complex-induced mast cell degranulation. Consistent with reduced intracellular glucocorticoid action in mast cells, levels of carboxypeptidase A3 mRNA, a glucocorticoid-inducible mast cell-specific transcript, are lower in peritoneal cells from 11β-HSD1-deficient than control mice. These findings suggest that 11β-HSD1-generated glucocorticoids may tonically restrain mast cell degranulation, potentially influencing allergic, anaphylactic and inflammatory responses
Recode-2: new design, new search tools, and many more genes
'Recoding' is a term used to describe non-standard read-out of the genetic code, and encompasses such phenomena as programmed ribosomal frameshifting, stop codon readthrough, selenocysteine insertion and translational bypassing. Although only a small proportion of genes utilize recoding in protein synthesis, accurate annotation of ‘recoded’ genes lags far behind annotation of 'standard' genes. In order to address this issue, provide a service to researchers in the field, and offer training data for developers of gene-annotation software, we have gathered together known cases of recoding within the Recode database. Recode-2 is an improved and updated version of the database. It provides access to detailed information on genes known to utilize translational recoding and allows complex search queries, browsing of recoding data and enhanced visualization of annotated sequence elements. At present, the Recode-2 database stores information on approximately 1500 genes that are known to utilize recoding in their expression—a factor of approximately three increase over the previous version of the database. Recode-2 is available at http://recode.ucc.i
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