900 research outputs found
Diamond thin Film Detectors for Beam Monitoring Devices
Diamonds offer radiation hard sensors, which can be used directly in primary
beams. Here we report on the use of a polycrystalline CVD diamond strip sensor
as beam monitor of heavy ion beams with up to 2.10^9 lead ions per bunch. The
strips allow for a determination of the transverse beam profile to a fraction
of the pitch of the strips, while the timing information yields the
longitudinal bunch length with a resolution of the order of a few mm.Comment: 6 pages, 7 figures, to appear in the Proceedings of the Hasselt
Diamond Workshop (Hasselt, Belgium, Feb. 2006), v4: accidentally submitted
figure, appearing at end, remove
Induction of osteoclast characteristics in cultured avian blood monocytes; modulation by osteoblasts and 1,25-(OH)2 vitamin D3
It has been established, that the osteoclast is derived from the haemopoietic stem cell, but its exact lineage is still controversial. It is sometimes suggested, that osteoclasts and monocytes/macrophages are related cells. It has also been suggested that osteoclast differentiation is regulated by osteoblasts and 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3). In the present paper we addressed the question whether avian monocytes can differentiate into osteoclasts in vitro, using an array of immunocytochemical, enzyme cytochemical and function markers. We have also determined the effects of osteoblasts, osteoblast conditioned medium and 1,25-(OH)2D3 on the expression of osteoclastic features on monocytes during culture. Monocytes developed tartrate resistant acid phosphatase (TRAcP) enzyme activity and antigens for all anti-osteoclast antibodies tested, during culture. However, they did not acquire the ability to resorb dentine and still showed phagocytosis of latex spheres. This indicates that the monocytes developed into cells resembling osteoclasts but lacking their function while retaining the function of macrophages. Osteoblast conditioned medium stimulated TRAcP enzyme activity and proliferation of monocytes in cultures. Addition of osteoblasts or osteoblast conditioned medium to monocyte cultures on dentine in the presence or absence of 1,25-(OH)2D3 did not result in the generation of genuine osteoclasts, nor in pit formation. 1,25-(OH)2D3 appeared to be cytotoxic to the avian monocytes in concentrations considered optimal for mouse osteoclast formation. These results suggest that avian monocytes do not readily differentiate into osteoclasts under in vitro conditions that stimulate osteoclast differentiation from bone marrow derived haemopoietic cells. Furthermore, labelling with anti-osteoclast antibodies and TRAcP as osteoclast-markers should be used only with great caution in the identification of osteoclasts formed in vitro
How does the substrate affect the Raman and excited state spectra of a carbon nanotube?
We study the optical properties of a single, semiconducting single-walled
carbon nanotube (CNT) that is partially suspended across a trench and partially
supported by a SiO2-substrate. By tuning the laser excitation energy across the
E33 excitonic resonance of the suspended CNT segment, the scattering
intensities of the principal Raman transitions, the radial breathing mode
(RBM), the G-mode and the D-mode show strong resonance enhancement of up to
three orders of magnitude. In the supported part of the CNT, despite a loss of
Raman scattering intensity of up to two orders of magnitude, we recover the E33
excitonic resonance suffering a substrate-induced red shift of 50 meV. The peak
intensity ratio between G-band and D-band is highly sensitive to the presence
of the substrate and varies by one order of magnitude, demonstrating the much
higher defect density in the supported CNT segments. By comparing the E33
resonance spectra measured by Raman excitation spectroscopy and
photoluminescence (PL) excitation spectroscopy in the suspended CNT segment, we
observe that the peak energy in the PL excitation spectrum is red-shifted by 40
meV. This shift is associated with the energy difference between the localized
exciton dominating the PL excitation spectrum and the free exciton giving rise
to the Raman excitation spectrum. High-resolution Raman spectra reveal
substrate-induced symmetry breaking, as evidenced by the appearance of
additional peaks in the strongly broadened Raman G band. Laser-induced line
shifts of RBM and G band measured on the suspended CNT segment are both linear
as a function of the laser excitation power. Stokes/anti-Stokes measurements,
however, reveal an increase of the G phonon population while the RBM phonon
population is rather independent of the laser excitation power.Comment: Revised manuscript, 20 pages, 8 figure
New Insights Into Legacy Phosphorus From Fractionation of Streambed Sediment
Streambed and lake sediment was studied in Savjaan, a eutrophic mesoscale catchment (722 km(2)) in central Sweden. Triplicate sediment cores from five lakes and nine streams, ranging from headwater to fourth order, were sampled. The sediment was analyzed with a sequential extraction method, where six different phosphorus (P) fractions were measured. The results showed that streambed sediments store considerable amounts of P and in some cases have comparable P contents (g/kg DW) to lake sediment. Land use, soil type, and drainage area (location in the catchment) had a significant effect on the different P fractions found in surficial sediments. Sediment from lakes and forested headwater streams generally had high proportions of organic P and iron bound P. In larger streams located in agricultural areas on clay soils closer to the catchment outlet, with dense sediment and a relatively low proportion of organic matter, P was to a larger extent bound to calcium. Streambed sediment may be an important catchment scale P store and should be considered when modeling catchment P dynamics. The large stores of streambed legacy P should also be considered when performing ditch maintenance to avoid unnecessary mobilization of bioavailable P
The orally administered P-glycoprotein inhibitor R101933 does not alter the plasma pharmacokinetics of docetaxel
This Phase I study was performed to assess the feasibility of combining
docetaxel with the new P-glycoprotein inhibitor R101933 and to determine
the dose limiting toxicity of this combination. Fifteen patients received
oral R101933 alone at a dose escalated from 200 to 300 mg twice daily
(b.i.d.; cycle 0), an escalating i.v. dose of docetaxel (60, 75, and 100
mg/m2) as a 1-h infusion (cycle 1), and the combination (cycle 2 and
further). Dose limiting toxicity consisting of mucositis and neutropenic
fever was reached at the combination of docetaxel, 100 mg/m2, and R101933,
300 mg b.i.d., and the maximum tolerated dose was established at
docetaxel, 100 mg/m2, and R101933, 200 mg b.i.d. Plasma concentrations of
R101933 achieved in patients were in the same range as required in
preclinical rodent models to overcome paclitaxel resistance. The plasma
pharmacokinetics of docetaxel were not influenced by the R101933 regimen
at any dose level tested, as indicated by plasma clearance values of 26.5
+/- 7.78 liters/h/m2 and 23.4 +/- 4.52 liters/h/m2 (P = 0.15) in cycles 1
and 2, respectively. These findings indicate that the contribution of a
P-glycoprotein inhibitor to the activity of anticancer chemotherapy can
now be assessed in patients for the first time independent of its effect
on drug pharmacokinetics
The relative importance of comprehensive performance measurement systems and financial performance measures on employeesâ perceptions of informational fairness
Research on how performance measurement systems affect employees' perceptions of workplace fairness is important. As organizations often rely on their performance measurement systems to communicate information to their employees, it is useful to ascertain if and how the developments of performance measurement systems that are far more comprehensive than traditional financial systems affect employees' perceptions of informational fairness through the information communicated to employees. Informational fairness refers to employees' perceptions of workplace fairness that is based on the amount and the truthfulness of information that organizations provide to their employees. Based on a sample of managers from manufacturing organizations, the Partial Least Square results indicate that comprehensive performance measurement systems (comprehensive PMS) have a significant direct effect on jobrelevant information. They also indicate that comprehensive PMS have an indirect effect on informational fairness via job-relevant information. In contrast, systems that are based on financial measures have no significant effects on job-relevant information and informational fairness. These results demonstrate how comprehensive PMS (through the communication of a greater amount of job-relevant information) can be used to engender employees' perceptions of high workplace fairnes
Signaling in Secret: Pay-for-Performance and the Incentive and Sorting Effects of Pay Secrecy
Key Findings: Pay secrecy adversely impacts individual task performance because it weakens the perception that an increase in performance will be accompanied by increase in pay; Pay secrecy is associated with a decrease in employee performance and retention in pay-for-performance systems, which measure performance using relative (i.e., peer-ranked) criteria rather than an absolute scale (see Figure 2 on page 5); High performing employees tend to be most sensitive to negative pay-for- performance perceptions; There are many signals embedded within HR policies and practices, which can influence employeesâ perception of workplace uncertainty/inequity and impact their performance and turnover intentions; and When pay transparency is impractical, organizations may benefit from introducing partial pay openness to mitigate these effects on employee performance and retention
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