Scientometrics - Using a selection of general science journals, general medical journals and specialized medical journals, this paper analyses four indicators of epistemic community formation:... 相似文献
Peanut allergy is a major cause of food‐induced severe anaphylactic reactions. To date, no medical care is available to prevent and treat peanut allergy and therefore hypoallergenic peanut varieties are of considerable health political and economic interest. Major allergens that induce IgE‐responses in peanut‐sensitive patients are Ara h 1, Ara h 2 and Ara h 3/4. In order to identify hypoallergenic peanuts, commercially locally available peanut varieties were screened for their allergen content. Ara h 1‐deficient peanuts from Southeast Asia were identified by SDS‐PAGE, immunoblotting, inhibition assays and ELISA. 2‐D PAGE analyses demonstrated the different compositions of the tested extracts and revealed a number of variations of the allergen patterns of peanuts from different varieties. Mediator release experiments of these peanut extracts demonstrated similar allergenicities as compared with standard peanut extract. These results indicate that the allergenicity of peanuts with reduced Ara h 1 content might be compensated by the other allergens, and thus do not necessarily cause a reduction of allergenicity. 相似文献
This paper presents a large-scale study of the phenomenon ‘uncitedness’. A literature review indicates that uncitedness is related to at least three factors: Field, document type, and time. To explore these factors and their mutual influence further, and at much larger scale than previous studies, the paper focuses on seven subject areas (arts and humanities; social sciences; computer science; mathematics; engineering; medicine; physics and astronomy), seven document types (articles; reviews; notes; letters; conference papers; books; book chapters), and a 20-year publication window (1996–2015). Documents are searched in Scopus, and retrieved year-by-year, discipline-by-discipline, and for each individual document type (total: 29,472,184 documents; 7,508,741 uncited documents). The results show great variance in uncitedness ratios between subject areas and document types. This is probably caused by a somewhat tacitly agreed upon genre hierarchy existing in all subject areas, yet with important local traits and differences. The importance of the time-dimension is documented. Time to first citation varies a great deal between subject areas, and the uncitedness ratio is consequently shown to be quite sensitive to the length of citation windows.
It is demonstrated that good thermal stability in Al-Mg-Si-Cu aluminum alloys correlates with a high density of fine lath-shaped, Cu-containing, disordered L-precipitates. Alloys optimized for L retained hardness above 90 HV after 3 weeks over-aging at 473 K (200 °C). Further improvement was achieved by substituting Si by Ge in one alloy. High-angle annular dark-field scanning transmission electron microscopy showed that at peak-hardness conditions, L coexists with more common needle-shaped precipitates, often with Cu-enriched interfaces. 相似文献
Large polymeric 3-alkylpyridinium salts have been isolated from the marine sponge Reniera sarai. They are composed of N-butyl(3-butylpyridinium) repeating subunits, polymerized head-to-tail, and exist as a mixture of two main polymers with molecular weights without counterion of about 5520 and 18900. The monomer analogue of the inhibitor, N-butyl-3-butylpyridinium iodide has been synthesized. This molecule shows mixed reversible inhibition of acetylcholinesterase. The polymers also act as acetylcholinesterase inhibitors and show an unusual inhibition pattern. We tentatively describe it as quick initial reversible binding, followed by slow binding or irreversible inhibition of the enzyme. This kinetics suggests that there are several affinity binding sites on the acetylcholinesterase molecule where the polymer can bind. The first binding favors binding to other sites which leads to an apparently irreversibly linked enzyme-inhibitor complex. 相似文献
Measurements of the integrated far field from a single-mode fibre using a simple set-up for attenuation measurements yields the spot size of the equivalent Gaussian field, or the ESI parameters. Using a multilayer method for calculating the field in the fibre, it is shown that the obtained spot size (ESI values) will depend on how this parameter is extracted. 相似文献
Ohne Zusammenfassung
Mitteilung aus dem Institut der Forschungsgemeinschaft für die Kühllagerung von Gemüse und Obst e.V., Magdeburg.
Vorgetragen bei der vom Forschungsdienst und dem Verein Deutscher Ingenieure veranstalteten Gefriertechnischen Tagung in Karlsruhe
am 26. und 27. November 1943. 相似文献
Ultra-high-resolution spectroscopy and metrology require very stable lasers with a high-spectral purity. For spectroscopy with a resolution in the range 10-100 Hz at 30 THz, we are developing a new stabilization scheme which acts separately on the long and short term stabilities. We present the results achieved with the first part of our new scheme, which is based upon the stabilization on a saturation signal detected in transmission of an active Fabry-Perot cavity. With a laser linewidth of 3.4 Hz (FWHM) and a flicker plateau of 0.7 Hz (Δν/ν=2.10-14) obtained using a strong OsO4 line as reference, this stabilization system already improves the both short and long-term stabilities obtained by our previous setup which involved an external cell instead of a Fabry-Perot cavity. We present also the results using a CO2 laser line as frequency reference 相似文献