100,436 research outputs found
Waveguide Mode Reflectometry for Obstacle Detection in the LHC Beam Pipe Including Signal Attenuation
No full textUnexpected obstacle formation in the LHC beam-pipe during assembly, cool down and operation may lead to major disturbances. Thus a fast, precise, sensitive and reliable means to detect and characterize such a fault is highly desirable, preferably without the need to break the vacuum. Waveguide mode time domain reflectometry using the synthetic pulse technique has been selected for this purpose. The system will use a modern vector network analyzer operating using essentially the fundamental TM mode on the LHC beam-screen. The objective is to measure over a full arc with access from either side both in reflection and transmission mode. If the proposed system is implemented a total of 32 couplers will be permanently installed, which may be used in normal operation for beam diagnostics and other applications. The attenuation of several short beam-screen sections has been measured both for TE and TM modes by means of a resonator method and these data are compared with theoretical results. Waveguide calibration on the beam-pipe and digital signal processing to compensate dispersion are studied. Finally, using a 44m test track the performance of the proposed methods is examined
Evidence for occurrence of an organophosphate-resistant type of acetylcholinesterase in strains of sea lice (Lepeophtheirus salmonis Kroyer)
No full textAcetylcholinesterase (AChE) is the target of a major pesticide family, the organophosphates, which were extensively used as control agents of sea lice on farmed salmonids in the early 1990s. From the mid-1990s the organophosphates dichlorvos and azamethiphos were seriously compromised by the development of resistance. AChE insensitive to organophosphate chemotherapeutants has been identified as a major resistance mechanism in numerous arthropod species, and in this study, target-site resistance was confirmed in the crustacean Lepeophtheirus salmonis Kroyer isolated from several fish-farming areas in Norway and Canada. A bimolecular rate assay demonstrated the presence of two AChE enzymes with different sensitivities towards azamethiphos, one that was rapidly inactivated and one that was very slowly inactivated. To our knowledge this is the first report of target-site resistance towards organophosphates in a third class of arthropods, the Crustacea. (C) 2004 Society of Chemical Industr
Redescription of Chone infundibuliformis Kroyer, 1856 (Polychaeta : Sabellidae) and histology of the branchial crown appendages, collar and glandular ridge
No full textFifty-three species have been formally described in Chone Kroyer, 1856, showing wide variation in the shapes of dorsal lips, peristomium, and posterior abdominal uncini. Previous studies indicate that such variation could result in splitting of the genu
Letter, [Author unclear] to Paulina T. Merritt
No full textHandwritten letter to Paulina Merritt from an unknown author, October 1, 1876.
Nutritional bioactive and antioxidant properties of selected fruit seeds
No full textNutritional bioactive and antioxidant properties of selected fruit seeds
G. T. KROYER
Department of Natural Products and Food Chemistry, Institute of Chemical Engineering, University of Technology, Getreidemarkt 9, A-1060 Vienna, Austria
There is a growing interest in the food industry and in preventive health care in the evaluation of natural nutritives with antioxidant properties. Consumption of a diet rich in antioxidant active polyphenol compounds has been linked with a reduced risk for cardiovascular diseases and certain types of cancer. The objective of this study was to quantify the total polyphenol compounds and to evaluate the antioxidant and free radical scavenging properties of seed extracts of pomegranate, papaya and melon.
The ground seeds were dried and extracted with 80% ethanol in water. The obtained solid extracts were analyzed for their content of total polyphenols (Folin-Ciocalteu method). The antioxidant activities were determined with the DPPH* radical scavenging method in terms of their Efficient Concentration EC50 (mg antioxidant /mg DPPH*).
All the seed extracts showed remarkable amounts of total polyphenols and considerable free radical scavenging activity (EC50). Comparatively, the amount of total polyphenols (mg/g) in the seed extracts decreased in the order papaya (20,9) > pomegranate (9,9) > melon (3,5). Correlating with the polyphenol content, the extract of papaya seeds proved to have the highest antioxidant properties (EC50: 6,2), followed by the pomegranate seed extract (EC50: 10,1), whilst the extract of melon seeds showed only relatively poor inhibitory effectiveness (EC50: 28,4).
The results indicate that fruit seed extracts, above all papaya seed extracts, have remarkable antioxidant properties in correlation with their total polyphenol content. An application as functional natural antioxidant food additive and as health promoting dietary supplement seems to be worth considering
Handwritten biographical information on Paulina T. McClung Merritt
No full textA handwritten biography of Paulina T. McClung Merritt by an unknown author, 1892.
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Pelevin’s Trinity in the novel “t”: author – protagonist – reader
No full textThe article attempts to interpret Pelevin's artistic strategy in the novel "T" by exploring its subject organization and addressing the key problems of the author, the protagonist, and the reader as they are seen by the researcher. The article analyzes the peculiarities of constructing the narrative reality in the novel "T", and goes on to discuss Pelevin's philosophic models of the development of the humankind, and the emergence of his new anthropology
Bioaktive Inhaltsstoffe und antioxidative Aktivität von Kakao und Schokolade
No full textBIOAKTIVE INHALTSSTOFFE UND ANTIOXIDATIVE AKTIVITÄT VON
KAKAO UND SCHOKOLADE
Kroyer G., Molnar T.
Institut für Verfahrenstechnik. Umwelttechnik und Technische Biowissenschaften
Technische Universität Wien, Getreidemarkt 9, A-1060 Wien
Die aktuellen Entwicklungen auf dem Lebensmittelsektor lassen ein wachsendes Interesse an ernährungsphysiologisch wirksamen "funktionellen Lebensmitteln" mit dem Aspekt einer präventiven Gesundheitsförderung erkennen. Insbesondere wird in diesem Zusammenhang der Entwicklung und Evaluierung von antioxidativ bzw. als Radikalfänger wirkenden Lebensmitteln und Lebensmittelkomponenten, die aus natürlichen pflanzlichen Rohstoffen gewonnen werden, vorrangige Bedeutung beigemessen.
Kakao und Kakao-Produkte, insbesondere Schokolade, enthalten beachtliche Mengen an polyphenolischen Substanzen, die aufgrund ihrer potentiellen antioxidativen Aktivität und Radikalfänger-Eigenschaften von grundlegender funktioneller ernährungsphysiologischer Bedeutung sein können.
Das Ziel dieser Studie lag in der vergleichsweisen Evaluierung des Gehaltes an polyphenolischen Inhaltsstoffen (Gesamtpolyphenole, Flavonoide, Katechine, Proanthocyanidine) sowie der antioxidativen Aktivität und Radikalfänger-Eigenschaften von Kakoapulver und verschiedenen in Österreich hergestellten Schokolade-Produkten mit unterschiedlichen Kakao-Anteilen.
Sämtliche Kakao- und Schokolade-Produkte zeichnen sich durch einen hohen Gehalt an Gesamt-Polyphenolen, Flavonoiden, Katechinen und Proanthocyanidinen aus, wobei Kakaopulver die höchsten Mengen aufwies, gefolgt von den Schokolade-Produkten in Reihenfolge ihres prozentuellen Kakao-Anteils. Desgleichen zeigen sämtliche Kakao- und Schokolade-Produkte signifikant hohe antioxidative und Radikalfänger-Aktivitäten in Abhängigkeit von ihrem Kakao-Anteil. Eine enge Korrelation zwischen dem Gehalt an polyphenolischen Inhaltsstoffen und der Radikalfänger-Aktivität kann abgeleitet werden.
Demnach kann gefolgert werden, dass Kakao und Schokolade-Produkte aufgrund ihrer signifikanten antioxidativen und Radikalfänger-Aktivität sowie ihres beträchtlichen Gehaltes an polyphenolischen Substanzen als ernährungsphysiologisch effektives und hochqualitatives funktionelles diätetisches Nahrung-Supplement angesehen werden können unter besonderer Berücksichtigung ihrer gesundheitsfördernden Eigenschaften
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