2,851 research outputs found
Metallized polymeric foam material
Open-celled polyurethane foams can be coated uniformly with thin film of metal by vapor deposition of aluminum or by sensitization of foam followed by electroless deposition of nickel or copper. Foam can be further processed to increase thickness of metal overcoat to impart rigidity or to provide inert surface with only modest increase in weight
Dobutamine stress echocardiography in a patient with Wolff-Parkinson-White syndrome
We describe the case of a patient with ventricular pre-excitation who underwent dobutamine
stress echocardiography to evaluate atypical chest pain. The patient safely underwent the
procedure with interesting electrocardiographic findings during pharmacological stress. The
risks of dobutamine stress testing, along with possible explanations of this observed event, are
discussed. In conclusion, the safety of dobutamine stress testing in patients with ventricular
pre-excitation has not been established; further prospective studies are needed to decide whether
dobutamine stress testing is safe in certain subsets of this population. (Cardiol J 2011; 18, 4:
437–440
Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate
Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neuron
Norden, reframed
This paper calls for Norden to be understood as a metaframe. Related formulations like “Nordic art” or “Nordic welfare” function as mesoframes. These trigger multiple framing devices. A cache of related framing devices constitutes a framing archive. Framing devices work best when operating unobtrusively such that inclusions, exclusions and inconsistencies are condoned or naturalised. Their artifice, however, becomes apparent whenever a frame is questioned. Questioning or criticising a frame gives rise to a framing dispute. The theoretical justification for these typologies is provided at the outset. This schema is then applied to a select range of empirical examples drawn largely from the disciplinary frames (Ernst 1996) of art history and museum studies. Despite this specificity it is envisaged that the general principles set out below can and will be used to address a variety of devices, disputes and archives in Norden and beyond
A Counts-in-Cells Analysis of Lyman-break Galaxies at z~3
We have measured the counts-in-cells fluctuations of 268 Lyman-break galaxies
with spectroscopic redshifts in six 9 arcmin by 9 arcmin fields at z~3. The
variance of galaxy counts in cubes of comoving side length 7.7, 11.9, 11.4
h^{-1} Mpc is \sigma_{gal}^2 ~ 1.3\pm0.4 for \Omega_M=1, 0.2 open, 0.3 flat,
implying a bias on these scales of \sigma_{gal} / \sigma_{mass} = 6.0\pm1.1,
1.9\pm0.4, 4.0\pm0.7. The bias and abundance of Lyman-break galaxies are
surprisingly consistent with a simple model of structure formation which
assumes only that galaxies form within dark matter halos, that Lyman-break
galaxies' rest-UV luminosities are tightly correlated with their dark masses,
and that matter fluctuations are Gaussian and have a linear power-spectrum
shape at z~3 similar to that determined locally (\Gamma~0.2). This conclusion
is largely independent of cosmology or spectral normalization \sigma_8. A
measurement of the masses of Lyman-break galaxies would in principle
distinguish between different cosmological scenarios.Comment: Accepted for publication in ApJ, 16 pages including 4 figure
Perceptions of the Family Mealtime Environment and Adolescent Mealtime Behavior: Do Adults and Adolescents Agree?
The family mealtime environment has great potential to affect the eating behaviors of youth in the family. It is difficult to determine the important elements of a healthy mealtime environment because a valid assessment of the family environment is so difficult to obtain. The objective of this study is to examine the level of agreement between adult and adolescent perceptions of the family mealtime environment and adolescent mealtime behavior. A telephone survey was used to query adult and adolescent family members about how they perceive the family mealtime environment and the adolescent\u27s mealtime behavior. A convenience sample of 282 adult/adolescent pairs from four schools in the Minneapolis/St. Paul area completed the telephone surveys. Frequencies of responses and the associations between the adult and adolescent responses are presented. Pearson correlations and regression were used to examine the level of association between adult and adolescent responses. Mixed-model regression was used for the continuous variables, and mixed-model logistic regression was used for the dichotomous variables. This study showed very little concordance between adolescent and adult responses. Only one question regarding arguments about eating during mealtime showed concordance. Adults and adolescents living in the same household seem to have different perceptions of the family mealtime environment and adolescent eating patterns. Researchers need to be aware of and concerned with the validity of the use of self-report for descriptions of family mealtime. They also need to be aware of the difference in adult and adolescent perceptions and consider these differences when designing messages for the family
Demonstration of long-lived high power optical waveguides in air
We demonstrate that femtosecond filaments can set up an extended and robust
thermal waveguide structure in air with a lifetime of several milliseconds,
making possible the very long range guiding and distant projection of high
energy laser pulses and high average power beams. As a proof of principle, we
demonstrate guiding of 110 mJ, 7 ns, 532 nm pulses with 90% throughput over ~15
Rayleigh lengths in a 70 cm long air waveguide generated by the long timescale
thermal relaxation of an array of femtosecond filaments. The guided pulse was
limited only by our available laser energy. In general, these waveguides should
be robust against the effects of thermal blooming of extremely high average
power laser beams.Comment: 11 pages, 5 figure
Associations between Perceived Family Meal Environment and Parent Intake of Fruit,Vegetables, and Fat
Objective
To describe the family mealtime environment and assess associations with adult fruit, vegetable, and fat intake. Design
Telephone survey. Participants
A convenience sample of 277 adults in the Minneapolis/St. Paul area were recruited through 4 schools. The sample was 85% female and 70% married. The mean number of children in the household was 2.6 (range 1 to 9). Variables Measured
Adult fruit and vegetable intake, fat intake, and perceptions of the mealtime environment. Analysis
Descriptive and mixed-model linear regression. Results
Participants reported that the television was frequently on during dinner meals and almost one third felt that their family was too busy to eat dinner together. A higher frequency of television viewing during dinner was associated with lower fruit and vegetable consumption and higher fat consumption. Planning meals in advance was associated with higher fruit and vegetable consumption; however, 46% of the adults did not plan meals in advance. Arguments concerning eating behavior during dinner were associated with higher fat consumption. Conclusion and Implications
The family meal environment is associated with adult eating patterns and should be considered when designing nutrition messages for families
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