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941.
942.
Lipoprotein(a), atherosclerosis and thrombosis 总被引:1,自引:0,他引:1
G H Dahlén 《Progress in lipid research》1991,30(2-3):189-194
Lipoprotein(a) denotes cholesterol-rich particles similar to low density lipoproteins but characterized by an extra large hydrophilic glycoprotein, Apo(a), added to low density lipoproteins. Apolipoprotein(a) is bound to ApoB-100 by a disulfide bridge. Eleven different Apo(a) isoforms of varying sizes coded for by alleles at the Apo(a) gene locus on chromosome 6 have been identified, ranging in Mr between roughly 400-800 kDa. The level of lipoprotein(a) is inversely correlated with isoform size. A strong independent association between high lipoprotein(a) levels and atherosclerotic disorders is documented. Lipoprotein(a) is selectively retained in the intima and engulfed by macrophages in unmodified form. Human Apo(a) is very similar to plasminogen, which suggests that lipoprotein(a) represents a link between atherosclerosis and thrombosis. 相似文献
943.
Nuttakan Wongfun Michael Plötze Gerhard Furrer Helmut Brandl 《Geomicrobiology journal》2014,31(2):93-100
The dissolution potential of five cyanogenic bacteria was studied at 25°C during 32 days using granite material from the Damma glacier (Central Alps, Switzerland) as the sole source of nutrients. The bacterial species Pseudomonas fluorescens and Pseudomonas sp. CCOS 191 were the most effective to exudate various organic acids and consequently mobilized Fe. The molecular mechanisms include both, proton-promoted and ligand-promoted dissolution, preferentially at pH below 5 and in the pH range between 5.0 and 5.8, respectively. In addition, bacterially produced cyanide plays a minor role through the formation of soluble hexacyanoferrate complexes. To our knowledge, this study is the first that reveals the direct measurement of metal-cyanide complexes formed during biotic granite weathering. 相似文献
944.
Gerhard Tutz 《Biometrical journal. Biometrische Zeitschrift》1991,33(5):519-527
Direct kernels, due to LAUDER (1983), as an alternative to the indirect kernel method in discriminant analysis are considered. It is shown that direct kernels may be based on any kernel function known in discrete density estimation. The choice of smoothing parameters is based on general loss functions and a family of loss functions which are specific for the discrimination problem is introduced. Examples with distance dependent and distance independent smoothing parameters are given to illustrate the applicability. 相似文献
945.
946.
Cloning of the genes encoding urease from Proteus vulgaris and sequencing of the structural genes 总被引:16,自引:0,他引:16
A fragment of chromosomal DNA from proteus vulgaris encoding urease was cloned and expressed in Escherichia coli. A 3 kbp region was sequenced and revealed three open reading frames with homology to jack bean (Canavalia ensiformis) urease. The smallest protein (11 kDa) was homologous to the N-terminus of the plant enzyme and the largest polypeptide (61 kDa) corresponded to the C-terminus. The large protein contained conserved regions and a cysteine residue which is known to be catalytically important in the plant enzyme. A protein of 12 kDa showed homology to residues 132 to 237 of jack bean urease. 相似文献
947.
Rye bread and synthetic bread odorants – effective trap bait and lure for German cockroaches
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Bread‐in‐beer and bread‐in‐water are prevalent home recipe trap baits for attracting German cockroaches (GCRs), Blattella germanica (L.) (Dictyoptera: Blattellidae), which are significant urban pests. Our objectives were to (1) test the attractiveness of these baits, (2) study the underlying factors of GCR attraction, and (3) determine whether a blend of synthetic bread odorants could replace bread in a trap lure. In large‐arena laboratory experiments with laboratory‐reared GCR males, traps baited with rye bread not only captured eightfold more males than unbaited control traps but also most males released into bioassay arenas. Neither beer nor water enhanced the attractiveness of bread. Bread crust as a bait was more effective than bread crumbs. As Porapak Q headspace volatile extracts of rye bread attracted GCRs, all rye bread odorants in extracts were identified by gas chromatography‐mass spectrometry. Synthetic rye bread odorants and other known bread odorants were then assembled into a master blend. This master blend, and even partial blends lacking certain groups of organic volatiles such as aldehydes and ketones, proved very attractive to GCRs. We conclude that rye bread could be used as an effective bait in retainer traps or, laced with insecticide, as a food source in bait stations. A lure of synthetic bread odorants may eventually replace bread as bait, but the minimum number of essential odorants for that lure has yet to be determined. 相似文献
948.
949.
Emission analysis of Tb3+‐and Sm3+‐ion‐doped (Li2O/Na2O/K2O) and (Li2O + Na2O/Li2O + K2O/K2O + Na2O)‐modified borosilicate glasses
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B. Naveen Kumar Reddy S. Sailaja K. Thyagarajan Young Dahl Jho B. Sudhakar Reddy 《Luminescence》2018,33(3):486-494
Four series of borosilicate glasses modified by alkali oxides and doped with Tb3+ and Sm3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B2O3 + 10SiO2 + 5MgO + R + 0.5(Tb2O3/Sm2O3) [where R = 10(Li2O /Na2O/K2O) for series A and C, and R = 5(Li2O + Na2O/Li2O + K2O/K2O + Na2O) for series B and D]. The X‐ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5D4 → 7F5 (543 nm) transition of the Tb3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm3+ ions with the series C and D glasses showed strong reddish‐orange emission at 600 nm (4G5/2 →6H7/2) with an excitation wavelength λexci = 404 nm (6H5/2→4F7/2). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb3+ and Sm3+ ions was studied to optimize the potential alkali‐oxide‐modified borosilicate glass. 相似文献
950.
Suzanne T. E. Lommen Caspar A. Hallmann Eelke Jongejans Bruno Chauvel Melinda Leitsch-Vitalos Alla Aleksanyan Peter Tóth Cristina Preda Maja Šćepanović Huseyin Onen Barbara Tokarska-Guzik Paulina Anastasiu Zita Dorner Annamária Fenesi Gerhard Karrer Katalin Nagy Gyula Pinke Viktor Tiborcz Gergely Zagyvai Mihály Zalai Gabriella Kazinczi Robert Leskovšek Danijela Stešević Guillaume Fried Levani Kalatozishvili Andreas Lemke Heinz Müller-Schärer 《Biological invasions》2018,20(6):1475-1491
To better manage invasive populations, it is vital to understand the environmental drivers underlying spatial variation in demographic performance of invasive individuals and populations. The invasive common ragweed, Ambrosia artemisiifolia, has severe adverse effects on agriculture and human health, due to its vast production of seeds and allergenic pollen. Here, we identify the scale and nature of environmental factors driving individual performance of A. artemisiifolia, and assess their relative importance. We studied 39 populations across the European continent, covering different climatic and habitat conditions. We found that plant size is the most important determinant in variation of per-capita seed and pollen production. Using plant volume as a measure of individual performance, we found that the local environment (i.e. the site) is far more influential for plant volume (explaining 25% of all spatial variation) than geographic position (regional level; 8%) or the neighbouring vegetation (at the plot level; 4%). An overall model including environmental factors at all scales performed better (27%), including the weather (bigger plants in warm and wet conditions), soil type (smaller plants on soils with more sand), and highlighting the negative effects of altitude, neighbouring vegetation and bare soil. Pollen and seed densities varied more than 200-fold between sites, with highest estimates in Croatia, Romania and Hungary. Pollen densities were highest on arable fields, while highest seed densities were found along infrastructure, both significantly higher than on ruderal sites. We discuss implications of these findings for the spatial scale of management interventions against A. artemisiifolia. 相似文献