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991.
A survey of anthocyanins in axial bulbils and flowers of four Saxifraga species indicates the origin of the endemic Saxifraga svalbardensis to be by hybridization between S. hyperborea and S. cernua. The detection of anthocyanins seems reliable in herbarium material 50 years of age. 相似文献
992.
Steinar Økland 《Zoomorphology》1980,96(1-2):1-19
Summary The ultrastructure of the auricles, the ostia, and the ventricle of L. asellus and T. marmorea is described. The heart wall consists of an epicardium, a basement membrane, and an inner loose myocardium. The epicardial cells of the auricle are podocytes. The exposed cell body and the branched processes show pedicles. Ventricular epicardium is flat and simple. The slender, unbranched, mononucleated muscle fibres have a peripheral nucleus located midway along the fibre. Mitochondria are peripherally located, leaving the center to longitudinally running thick and thin myofilaments. Dense bodies and attachment plaques make up the Z-material. Sarcomeres and myofibrils are absent, as are transverse tubules and intercalated disks. The sarcoplasmic reticulum consists of peripheral tubules and subsarcolemmal cisternae, some of which radiate, branch, and run between myofilaments. Couplings are lacking. Ventricular fibres in T. marmorea show nexuses and desmosomes; in L. asellus only nexuses. The muscular ostia are tubular, and muscle fibres resemble those of the ventricle; nexuses are detected in T. marmorea and desmosomes in L. asellus. The only nervous elements observed are some nerve processes, structurally similar to those of other molluscs.Supported by grants from the Norwegian Research Council for Science and Humanities 相似文献
993.
994.
995.
P. Ølholm-Larsen 《Human genetics》1979,46(1):65-74
Summary Three cases of acrodermatitis enteropathica (a. e.) from two nonrelated families are described. Two siblings had characteristic symptoms of a. e. in childhood. Both survived to adulthood without treatment, at which time the clinical picture became uncharacteristic of a. e. Even so, the serum zinc levels confirmed the diagnosis in both cases. The third case showed classic symptoms of a. e.; the patient had a greatly reduced serum zinc level and responded at once to treatment with zinc sulphate.Heterozygous carriers of the gene for a. e. have often had slightly reduced serum zinc levels. The value of this test could probably be improved by corresting the normal range of serum zinc for factors known to influence this, such as the patient's age and serum albumin level. The normal range ought also to be corrected for diural and postprandial variations of serum zinc. 相似文献
996.
Øyvind Hammer 《Historical Biology》2013,25(2-3):153-171
Suture lines are important in ammonoid taxonomy. Their complex morphologies, caused by iterated invaginations of the posterior body wall, can be explained using a mechano‐chemical model inspired by modem developmental models for epithelial folding in kidneys, lungs, teeth, mammary glands and other organs. A morphogen, organized to form a regular spacing pattern by reaction‐diffusion dynamics or similar processes, induces changes in cell shape and/or rate of proliferation, causing invagination and the formation of lobes. Interactions between mechanical and chemical effects, combined with expanding size due to overall growth, produce a “fractal”; pattern of smaller (secondary) invaginations superimposed on larger (primary) ones. The pattern of increasing sutural complexity that is observed in ammonoid evolution may be a simple heterochronic effect, that allowed iterated invagination to be extended to higher and higher levels of folding. In contrast with some earlier theories, the present model is based on the view that the development of ammonoid septa must have been under relatively strict genetic control. 相似文献
997.
Ingrid Hauser Aslak Einbu Kjetill Østgaard Hallvard F. Svendsen Francisco J. Cervantes 《Biotechnology letters》2013,35(2):219-224
Nitrogen and organic matter removal from reclaimer waste of a monoethanolamine (MEA) based CO2-capture plant was demonstrated in a pre-denitrification biofilm system. The reclaimer waste was generated from a 30 % (w/w) MEA solvent used for capturing CO2 from flue gas from a coal-fired power plant. MEA, N-(2-hydroxylethyl)glycine (HEGly) and 2-hydroxyethylformamide (HEF) were the major contaminants treated. Hydrolysis of MEA to ammonia and further oxidation of organic intermediates readily occurred in the pre-denitrification system with a hydraulic retention time of 7 h. The biofilm system achieved 98 ± 1 % removal of MEA and 72 ± 16 % removal of total nitrogen. This is the first demonstration of efficient biodegradation of real amine waste from a post-combustion CO2 capture facility by pre-denitrification without external electron donor. 相似文献
998.
Role of granivory and insectivory in the life cycle of the carabid beetle Amara similata 总被引:3,自引:0,他引:3
1. The cereal field carabid beetle Amara similata was selected to elucidate the role of seeds and insects as food sources. Three experiments were performed to rank different weed seeds and insects in terms of food value: (i) fecundity in relation to adult diet, (ii) larval survival in relation to diet and (iii) larval survival in relation to parental diet.
2. Seeds were found to be of high value and insects of low value both for adults and larvae. Adding insects to a seed diet gave no significant improvement. The value of single species of seeds varied within adults and larvae, but also between adults and larvae. This is the first report that Amara larvae are granivorous.
3. The value of different insects varied by species. Cereal aphid species were of the lowest value both for adult and larval beetles. On a diet of mixed insects, the adults were able to produce a low number of eggs but the larvae all died before pupation.
4. There was no simple relation between survival of the larvae and the quality of the parents' diet. 相似文献
2. Seeds were found to be of high value and insects of low value both for adults and larvae. Adding insects to a seed diet gave no significant improvement. The value of single species of seeds varied within adults and larvae, but also between adults and larvae. This is the first report that Amara larvae are granivorous.
3. The value of different insects varied by species. Cereal aphid species were of the lowest value both for adult and larval beetles. On a diet of mixed insects, the adults were able to produce a low number of eggs but the larvae all died before pupation.
4. There was no simple relation between survival of the larvae and the quality of the parents' diet. 相似文献
999.
1000.