1,084 research outputs found
Pain after Whole-Body Vibration Exposure is Frequency Dependent and Independent of the Resonant Frequency: Lessons from an in vivo Rat Model
This is the author accepted manuscript. The final version is available from ASME via the DOI in this recordData Availability: Supporting datasets have been uploaded as part of the supplementary material.Occupational whole-body vibration (WBV) increases the risk of developing low back and neck pain; yet, there has also been an increased use of therapeutic WBV in recent years. Although the resonant frequency (fr) of the spine decreases as the exposure acceleration increases, effects of varying the vibration profile, including peak-to-peak displacement (sptp), root mean squared acceleration (arms) and frequency (f), on pain onset are not known. An established in-vivo rat model of WBV was used to characterize the resonance of the spine using sinusoidal sweeps. The relationship between arms and fr was defined and implemented to assess behavioral sensitivity - a proxy for pain. Five groups were subjected to a single 30-minute exposure, each with a different vibration profile, and a sham group underwent only anaesthesia exposure. The behavioral sensitivity was assessed at baseline and for 7 days following WBV-exposure. Only WBV at 8Hz induced behavioral sensitivity, and the higher arms exposure at 8Hz led to a more robust pain response. These results suggest that the development of pain is frequency-dependent, but further research into the mechanisms leading to pain are warranted to fully understand which WBV profiles may be detrimental or beneficial.Department of DefenseCatherine Sharpe Foundatio
Starch mobilization in leaves
Starch mobilization is well understood in cereal endosperms, but both the pathway and the regulation of the process are poorly characterized in other types of plant organs. Arabidopsis leaves offer the opportunity for rapid progress in this area, because of the genomic resources available in this species and the ease with which starch synthesis and degradation can be monitored and manipulated. Progress in understanding three aspects of starch degradation is described: the role of disproportionating enzyme, the importance of phosphorolytic degradation, and new evidence about the involvement of a starch‐phosphorylating enzyme in the degradative process. Major areas requiring further research are outline
S100B brain expression and plasma concentrations in a preeclampsia rat model
Objective: To assess brain damage using the neuroinflammation marker S100B in a preeclampsia rat model.Methods: Non-pregnant and pregnant rats were infused with saline or low-dose-endotoxin on day 14 of pregnancy. S100B expression in the brain (immunohistochemistry) and S100B plasma concentrations (ELISA) were studied.Results: No differences in S100B expression in brain tissue were observed between the four groups. Pregnant endotoxin treated animals did not show increased levels of plasma S100B levels as compared with control pregnant rats, while significantly higher plasma S100B levels were found in non-pregnant endotoxin versus pregnant endotoxin infused rats.Conclusion: Pregnancy nor experimental preeclampsia, alter S100B in rat brain, or in plasma. Increased plasma S100B in non-pregnant endotoxin-treated rats may indicate brain injury in these rats, whereas pregnancy might be protective.</p
Field intercomparison of prevailing sonic anemometers
Three-dimensional sonic anemometers are the core component of eddy covariance
systems, which are widely used for micrometeorological and ecological
research. In order to characterize the measurement uncertainty of these
instruments we present and analyse the results from a field intercomparison
experiment of six commonly used sonic anemometer models from four major
manufacturers. These models include Campbell CSAT3, Gill HS-50 and R3, METEK
uSonic-3 Omni, R. M. Young 81000 and 81000RE. The experiment was conducted
over a meadow at the TERENO/ICOS site DE-Fen in southern Germany over a
period of 16 days in June of 2016 as part of the ScaleX campaign. The
measurement height was 3 m for all sensors, which were separated by 9 m
from each other, each on its own tripod, in order to limit contamination of
the turbulence measurements by adjacent structures as much as possible.
Moreover, the high-frequency data from all instruments were treated with the
same post-processing algorithm. In this study, we compare the results for
various turbulence statistics, which include mean horizontal wind speed,
standard deviations of vertical wind velocity and sonic temperature, friction
velocity, and the buoyancy flux. Quantitative measures of uncertainty, such
as bias and comparability, are derived from these results. We find that
biases are generally very small for all sensors and all computed variables,
except for the sonic temperature measurements of the two Gill sonic
anemometers (HS and R3), confirming a known transducer-temperature dependence
of the sonic temperature measurement. The best overall agreement between the
different instruments was found for the mean wind speed and the buoyancy
flux
Fuzzy Topology, Quantization and Gauge Invariance
Dodson-Zeeman fuzzy topology considered as the possible mathematical
framework of quantum geometric formalism. In such formalism the states of
massive particle m correspond to elements of fuzzy manifold called fuzzy
points. Due to their weak (partial) ordering, m space coordinate x acquires
principal uncertainty dx. It's shown that m evolution with minimal number of
additional assumptions obeys to schroedinger and dirac formalisms in
norelativistic and relativistic cases correspondingly. It's argued that
particle's interactions on such fuzzy manifold should be gauge invariant.Comment: 12 pages, Talk given on 'Geometry and Field Theory' conference,
Porto, July 2012. To be published in Int. J. Theor. Phys. (2015
Relativistic Effects of Light in Moving Media with Extremely Low Group Velocity
A moving dielectric medium acts as an effective gravitational field on light.
One can use media with extremely low group velocities [Lene Vestergaard Hau et
al., Nature 397, 594 (1999)] to create dielectric analogs of astronomical
effects on Earth. In particular, a vortex flow imprints a long-ranging
topological effect on incident light and can behave like an optical black hole.Comment: Physical Review Letters (accepted
Comparing community structure on shells of the abalone Haliotis midae and adjacent rock: implications for biodiversity
This paper concerns the effects on biodiversity of depletion 24 of the South African
abalone Haliotis midae, which is a long-lived species with a large corrugated shell
that provides a habitat for diverse benthic organisms. We compared community
structure on H. midae shells with that on adjacent rock at three sites (Cape Point and
Danger Point sites A and B), and at two different times of the year at one of these
sites. Shells of H. midae consistently supported communities that were distinctly
different from those on rock. In particular, three species of non-geniculate
(encrusting) corallines, Titanoderma polycephalum, Mesophyllum engelhartii and
Spongites discoideus were all found either exclusively or predominantly on shells,
whereas another non-geniculate coralline, Heydrichia woelkerlingii, occurred
almost exclusively on adjacent rock. The primary rocky substratum, however,
supported a higher number of species than abalone shells. Possible reasons for the
differences between the two substrata include the relative age, microtopography and
hardness of the substrata; the abundance of grazers on them; and the relative age of
different zones of the abalone shell, which support communities at different stages of
succession. Diversity on shells was lowest in zones that were either very young or
very old, in keeping with the intermediate disturbance hypothesis. The
distinctiveness of shell epibiota will increase diversity despite having a lower
diversity than that of adjacent rock. Decimation of H. midae by overfishing therefore
has implications biodiversity conservation.Web of Scienc
Oestrogen removal from biological pretreated wastewater within decentralized sanitation and re-use concepts
Two parallel researches were performed; one focused on the fate of oestrogens in the biological treatment systems within decentralised sanitation and re-use concepts (DESAR), the second related to the development of a suitable specific removal method. A new affinity membrane was developed using antibodies as specific binding sites for hormone removal. It was found that, especially in anaerobic treatment, the core technology in DESAR, the removal is insufficient and therefore an additional separation method is required. The affinity membrane with antibodies was found to be a suitable additional method, though in the current system it only removes one selected compound. Future research will focus on making this method more feasible in practis
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