549 research outputs found
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Measuring conditions for second order X-ray Bragg-spectrometry
The KL2,3 (α)1,2-lines of 19K, the L3M4,5 (α)1,2-lines of 48Cd, and the M5N6,7 (α)1,2-lines of 92U are lines of comparable energy in the region of approximately 3 keV. In none of these cases were we able to resolve the three doublets when recording the spectra in first order Bragg spectrometry using a PET crystal as the dispersing element. For the purpose of enhancing the resolving power of the spectrometer, the three α spectra were recorded in second order reflection, thereby transferring the lines into another spectral region dominated by X-ray quanta of half the energy. In order to achieve high net peak intensities as well as a high peak-to-background ratio and, consequently, a high level of detection capability, the discriminator settings should be optimized quite carefully. In this manner, we were able to resolve the three α doublets and estimate α2/α1 intensity ratios. Inexplicably, current monographs, e.g., by Goldstein et al, do not contain any indications about the rational use of high order spectrometry. Only a few rather old monographs contain some hints in this regard
Surface-Enhanced Raman Scattering Microspectroscopy Enables the Direct Characterization of Biomineral-Associated Organic Material on Single Calcareous Microskeletons
Biominerals are composite materials with inorganic and organic components. The latter provide insights into how organisms control mineralization and, if derived from micro/nannofossils, into past climates. Many calcifying organisms cannot be cultured or are extinct; the only materials available for their study are therefore complex environmental samples in which the organism of interest may only be a minor component. There is currently no method for characterizing the biomineral-associated organic material from single particles within such assemblages, so its compositional diversity is unknown. Focusing on coccoliths, we demonstrate that surface-enhanced Raman scattering microspectroscopy can be used to determine the origin and composition of fossil organic matter at the single-particle level in a heterogeneous micro/nannofossil assemblage. This approach may find applications in the study of micro/nannofossil assemblages and uncultivated species, providing evolutionary insights into the macromolecular repertoire involved in biomineralization
Export destination and the skill premium: Evidence from Chinese manufacturing industries
This paper examines the relationship between average income of export destinations and the skill premium using data of Chinese manufacturing industries from 1995 to 2008. To do so, we construct weighted average GDP per capita across destinations employing within-industry export share to each destination as weights, and then link it with industry-level wages and the skill premium. We find that industries that export more to high-income destinations tend to pay a higher skill premium, suggesting that, on average, skilled workers benefit more from high-income exports than unskilled workers. Our IV estimates confirm a causal relationship, and the results are robust to various specifications. Further results based on firm-level data show consistent evidence. Our paper highlights the role of high-income destination exports in shaping the uneven distributional effects of globalization for different types of workers
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Influence of process parameters on the incorporation of phosphorus into silica soot material during MCVD process
The incorporation of phosphorus into silica soot material strongly changes during the multistep preparation process of the MCVD technology in combination with solution doping for Al and rare earths. We report on the influence of various process parameters on the phosphorus concentration, the bond types of phosphorus atoms and the relative density of the soot material. By optimization of the process the phosphorus concentration of the presintered soot could be increased by around 10% in comparison to the conventional treatment. The understanding of the interdependencies allows an improvement of the preparation process of phosphorus co-doped RE doped silica laser fibers with MCVD technology
Effects of rumensin and bovatec on growth, feed intake, and feed efficiency in dairy calves
One hundred Holstein heifers were used
to examine the effects of monensin
(RumensinÂź) and lasalocid (BovatecÂź)
included in calf starter and grower diets.
Heifers were assigned alternately at birth to a starter feed containing either Rumensin (28
g/ton, 90% dry matter basis) or Bovatec (40
g/ton, 90% dry matter basis). The Bovatec
group was switched to a starter feed containing
28 g Bovatec/ton (90% dry matter basis)
at 6 weeks of age. Both groups were
switched at 8 weeks of age to grower diets
designed to deliver 100 mg/head/day of either
Rumensin or Bovatec. No treatment differences
were observed between birth and 8
weeks of age. Heifers were moved from
individual hutches at 8 weeks of age to group
pens (five heifers/pen) and remained on the
same treatment for the next 84 days. During
this 84-day period, heifers receiving
Rumensin gained more weight at a faster rate
and tended to be more efficient than heifers
fed Bovatec. No differences were observed
in feed intake, skeletal growth as measured by
hip height, or body condition score
Key Action Extraction for Learning Analytics
Proceedings of: 7th European Conference on Technology Enhanced Learning (EC-TEL 2012): 21st Century Learning for 21st Century Skills. SaarbrĂŒcken, Germany, September 18-21, 2012.Analogous to keywords describing the important and relevant content of a document we extract key actions from learners' usage data assuming that they represent important and relevant parts of their learning behaviour. These key actions enable the teachers to better understand the dynamics in their classes and the problems that occur while learning. Based on these insights, teachers can intervene directly as well as improve the quality of their learning material and learning design. We test our approach on usage data collected in a large introductory C programming course at a university and discuss the results based on the feedback of the teachers.Work partially funded by the European Communityâs Seventh Framework Programme (FP7/2007-2013) under grant agreement no 231396 (ROLE project), the Learn3 project (TIN2008-05163/TSI), the eMadrid project (S2009/TIC-1650), and the AcciÂŽon Integrada DE2009-0051.Publicad
Bruton's tyrosine kinase inhibitionâAn emerging therapeutic strategy in immuneâmediated dermatological conditions
Bruton's tyrosine kinase (BTK), a member of the Tec kinase family, is critically involved in a range of immunological pathways. The clinical application of BTK inhibitors for B-cell malignancies has proven successful, and there is strong rationale for the potential benefits of BTK inhibitors in some autoimmune and allergic conditions, including immune-mediated dermatological diseases. However, the established risk-to-benefit profile of "first-generation" BTK inhibitors cannot be extrapolated to these emerging, non-oncological, indications. "Next-generation" BTK inhibitors such as remibrutinib and fenebrutinib entered clinical development for chronic spontaneous urticaria (CSU); rilzabrutinib and tirabrutinib are being studied as potential treatments for pemphigus. Promising data from early-phase clinical trials in CSU suggest potential for these agents to achieve strong pathway inhibition, which may translate into measurable clinical benefits, as well as other effects such as the disruption of autoantibody production. BTK inhibitors may help to overcome some of the shortcomings of monoclonal antibody treatments for immune-mediated dermatological conditions such as CSU, pemphigus, and systemic lupus erythematosus. In addition, the use of BTK inhibitors may improve understanding of the pathophysiological roles of mast cells, basophils, and B cells in such conditions.info:eu-repo/semantics/publishedVersio
Autologous serum skin test reactions in chronic spontaneous urticaria differ from heterologous cell reactions
Background: Autoimmune chronic spontaneous urticaria (CSU) is due to mast cell (MC)-activating autoantibodies, which are screened for by the autologous serum skin test (ASST) and basophil tests (BTs). Many CSU patients are positive in only one of these tests. How often this occurs and why is currently unknown.
Objectives: To characterize the prevalence of mismatched ASST and BTs in CSU patients, and to investigate possible reasons for these mismatches.
Methods: We determined the rates of ASST+/BT- and ASST-/BT+ mismatches in published CSU studies. We assessed sera from 48 CSU patients by ASST, two BTs (basophil histamine release assay, BHRA; basophil activation test, BAT), a MC histamine release assay (MCHRA) and by ex vivo skin microdialysis (SMD).
Results: The ASST/BT mismatch rate in published CSU studies was 31% (ASST+/BT-: 22%, ASST-/BT+: 9%). In our patients, the ASST/BHRA and ASST/BAT mismatch rate was 35.4% (ASST+/BHRA-: 18.8% and ASST-/BHRA+: 16.7%) and 31.3% (ASST+/BAT-: 6.3% and ASST-/BAT+: 25.0%), respectively, and the two BTs were significantly correlated (P = 0.0002). The use of heterologous MCs, in vitro and in situ, instead of basophils produced similar results (MCHRA mismatch: 47.9%, ASST+/MCHRA-: 18.8%, ASST-/MCHRA+: 29.2%; SMD mismatch: 40.0%, ASST+/SMD-: 10.0% and ASST-/SMD+: 30.0%), and the MCHRA was highly correlated with SMD results (P = 0.0002).
Conclusions: The ASST and BTs show divergent results in a third of CSU patients. Mismatches cannot be explained by the choice of basophil assay, the type of heterologous cells exposed to CSU serum in vitro (basophils vs. mast cells), nor the experimental setting of heterologous skin mast cells (in vitro vs. in situ). Thus, serum-induced whealing, in CSU patients, seems to involve autologous skin signals modulating MC degranulation
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