591 research outputs found
Strength Training with Superimposed Whole Body Vibration Does Not Preferentially Modulate Cortical Plasticity
Paired-pulse transcranial magnetic stimulation (TMS) was used to investigate 4 wks of leg strength training with and without whole body vibration (WBV) on corticospinal excitability and short-latency intracortical inhibition (SICI). Participants (n = 12) were randomly allocated to either a control or experimental (WBV) group. All participants completed 12 squat training sessions either with (WBV group) or without (control group) exposure to WBV (f = 35 Hz, A = 2.5 mm). There were significant (P < 0.05) increases in squat strength and corticospinal excitability and significant (P < 0.05) reductions in SICI for both groups following the 4 wk intervention. There were no differences detected between groups for any dependant variable (P > 0.05). It appears that WBV training does not augment the increase in strength or corticospinal excitability induced by strength training alone
No evidence for absence of solar dynamo synchronization
Context: The old question of whether the solar dynamo is synchronized by the
tidal forces of the orbiting planets has recently received renewed interest,
both from the viewpoint of historical data analysis and in terms of theoretical
and numerical modelling. Aims: We aim to contribute to the solution of this
longstanding puzzle by analyzing cosmogenic radionuclide data from the last
millennium. Methods: We reconsider a recent time-series of C-inferred
sunspot data and compare the resulting cycle minima and maxima with the
corresponding conventional series down to 1610 A.D., enhanced by Schove's data
before that time. Results: We find that, despite recent claims to the contrary,
the C-inferred sunspot data are well compatible with a synchronized
solar dynamo, exhibiting a relatively phase-stable period of 11.07 years, which
points to a synchronizing role of the spring tides of the Venus-Earth-Jupiter
system.Comment: 8 pages, 7 figure
The influence of current collectors on Tayler instability and electro-vortex flows in liquid metal batteries
The Tayler instability is a kink-type flow instability which occurs when the
electrical current through a conducting fluid exceeds a certain critical value.
Originally studied in the astrophysical context, the instability was recently
shown to be also a limiting factor for the upward scalability of liquid metal
batteries. In this paper, we continue our efforts to simulate this instability
for liquid metals within the framework of an integro-differential equation
approach. The original solver is enhanced by multi-domain support with
Dirichlet-Neumann partitioning for the static boundaries. Particular focus is
laid on the detailed influence of the axial electrical boundary conditions on
the characteristic features of the Tayler instability, and, secondly, on the
occurrence of electro-vortex flows and their relevance for liquid metal
batteries.Comment: 26 pages, 16 figure
IRF5 Is a Key Regulator of Macrophage Response to Lipopolysaccharide in Newborns.
Infections are a leading cause of mortality and morbidity in newborns. The high susceptibility of newborns to infection has been associated with a limited capacity to mount protective immune responses. Monocytes and macrophages are involved in the initiation, amplification, and termination of immune responses. Depending on cues received from their environment, monocytes differentiate into M1 or M2 macrophages with proinflammatory or anti-inflammatory and tissue repair properties, respectively. The purpose of this study was to characterize differences in monocyte to macrophage differentiation and polarization between newborns and adults. Monocytes from umbilical cord blood of healthy term newborns and from peripheral blood of adult healthy subjects were exposed to GM-CSF or M-CSF to induce M1 or M2 macrophages. Newborn monocytes differentiated into M1 and M2 macrophages with similar morphology and expression of differentiation/polarization markers as adult monocytes, with the exception of CD163 that was expressed at sevenfold higher levels in newborn compared to adult M1 macrophages. Upon TLR4 stimulation, newborn M1 macrophages produced threefold to sixfold lower levels of TNF than adult macrophages, while production of IL-1-β, IL-6, IL-8, IL-10, and IL-23 was at similar levels as in adults. Nuclear levels of IRF5, a transcription factor involved in M1 polarization, were markedly reduced in newborns, whereas the NF-κB and MAP kinase pathways were not altered. In line with a functional role for IRF5, adenoviral-mediated IRF5 overexpression in newborn M1 macrophages restored lipopolysaccharide-induced TNF production. Altogether, these data highlight a distinct immune response of newborn macrophages and identify IRF5 as a key regulator of macrophage TNF response in newborns
Potential and distribution of transplanted hematopoietic stem cells in a nonablated mouse model
Increasingly, allogeneic and even more often autologous bone marrow transplants are being done to correct a wide variety of diseases. In addition, autologous marrow transplants potentially provide an opportune means of delivering genes in transfected, engrafting stem cells. However, despite its widespread clinical use and promising gene therapy applications, relatively little is known about the mechanisms of engraftment in marrow transplant recipients. This is especially so in the nonablated recipient setting. Our data show that purified lineage negative rhodamine 123/Hoechst 33342 dull transplanted hematopoietic stem cells engraft into the marrow of nonablated syngeneic recipients. These cells have multilineage potential, and maintain a distinct subpopulation with stem cell characteristics. The data also suggests a spatial localization of stem cell niches to the endosteal surface, with all donor cells having a high spatial affinity to this area. However, the level of stem cell engraftment observed following a transplant of stem cells was significantly lower than that expected following a transplant of the same number of unseparated marrow cells from which the purified cells were derived, suggesting the existence of a nonstem cell facilitator population, which is required in a nonablated syngeneic transplant setting
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Radiation Doses to Hanford Workers from Natural Potassium-40
The chemical element potassium is an essential mineral in people and is subject to homeostatic regulation. Natural potassium comprises three isotopes, 39K, 40K, and 41K. Potassium-40 is radioactive, with a half life of 1.248 billion years. In most transitions, it emits a β particle with a maximum energy of 0.560 MeV, and sometimes a gamma photon of 1.461 MeV. Because it is ubiquitous, 40K produces radiation dose to all human beings. This report contains the results of new measurements of 40K in 248 adult females and 2,037 adult males performed at the Department of Energy Hanford Site in 2006 and 2007. Potassium concentrations diminish with age, are generally lower in women than in men, and decrease with body mass index (BMI). The average annual effective dose from 40K in the body is 0.149 mSv y−1 for men and 0.123 mSv y−1 women respectively. Averaged over both men and women, the average effective dose per year is 0.136 mSv y−1. Calculated effective doses range from 0.069 to 0.243 mSv y−1 for adult males, and 0.067 to 0.203 mSv y−1 for adult females, a roughly three-fold variation for each gender. The need for dosimetric phantoms with a greater variety of BMI values should be investigated. From our data, it cannot be determined whether the potassium concentration in muscle in people with large BMI values differs from that in people with small BMI values. Similarly, it would be important to know the potassium concentration in other soft tissues, since much of the radiation dose is due to beta radiation, in which the source and target tissues are the same. These uncertainties should be evaluated to determine their consequences for dosimetry
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