Search Results - (Author, Cooperation:T. Pfeiffer)

2016-03-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

0029-554X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Energy, Environment Protection, Nuclear Power Engineering

Physics

Electronic Resource

0167-8760

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Medicine

Psychology

Electronic Resource

1432-0630

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

Electronic Resource

0040-6090

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

0029-554X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Energy, Environment Protection, Nuclear Power Engineering

Physics

Electronic Resource

1433-0385

Key words: Aorta – Aneurysm – Aortic aneurysm – Aortic aneurysm, abdominal – Aortic aneurysm, abdominal surgery. ; Schlüsselwörter: Aorta – Aneurysma – Aortenaneurysma – abdominelles Aortenaneurysma – chirurgische Therapie.

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung. Einleitung: Anfang der 90er Jahre kam die endovasculäre Stentimplantation als neuartige Methode zur Behandlung des abdominellen Aortenaneurysmas (AAA) auf. Dies bot uns Anlaß, die eigenen Ergebnisse der offenen Chirurgie des AAA zu überprüfen, um die Frage der Standardtherapie des AAA neu zu überdenken. Methoden: Die medizinischen Daten von 941 konsekutiven Patienten mit AAA, die in unserer Klinik von 1990–1997 offen chirurgisch behandelt wurden (Durchschnittsalter 67 Jahre, 6 % über 80 Jahre, 14,5 % Frauen, 3,2 % suprarenale AAA), wurden retrospektiv analysiert. 778 asymtomatische Patienten wurden elektiv, 104 symptomatische Patienten wurden dringlich, und 59 symptomatische Patienten (davon 45 mit Perforation) wurden als Notfall operiert. Ergebnisse: Die Letalität betrug bei elektiven Operationen 1,54 %, bei dringlichen Operationen 8,65 % und bei Notfällen mit perforiertem AAA (unverzügliche Operation nach Aufnahme in die Klinik) 35,6 %. Die Morbidität lag bei elektiven Eingriffen bei 15,9 %, bei dringlichen Operationen bei 28,8 % und bei Notfalloperationen mit perforiertem AAA bei 66,7 %. Für Patienten mit zusätzlichen Eingriffen an Nieren-, Becken- und Beinarterien sowie Kombinationseingriffen in anderen Operationsgebieten war die Letalität im Vergleich zum Durchschnitt nicht erhöht. Schlußfolgerung: Aufgrund der niedrigen Letalität und Morbidität stellt die offene Chirurgie auch heute den gültigen Standard der AAA-Behandlung dar.

Summary. Introduction: In 1990 the new method of endovascular graft treatment of abdominal aortic aneurysms (AAA) emerged. For this reason we analyzed the results of open surgery for AAA in our department to consider the question of standard therapy. Methods: In a retrospective study the medical data of 941 consecutive patients treated by open surgery in a single center from 1990 to 1997 (mean age 67 years, 14.5 % female, 3.2 % suprarenal AAA) were analyzed. Operations were performed electively in 778 asymptomatic patients, urgently in 104 symptomatic patients, and as emergency operations (immediately after admission) in 59 symptomatic patients (45 patients presenting with rupture). Results: Mortality was 1.54 % (elective operations), 8.65 % (urgent operations), and 35.6 % (emergency operations, rupture). Morbidity was 15.9 % (elective operations), 28.8 % (urgent operations), and 66.7 % (emergency operations, rupture). Mortality was not increased in patients undergoing additional procedures of the renal, iliac, femoral, or crural arteries. Conclusion: Because of its low mortality and morbidity today open surgical repair remains the standard therapy for AAA.

Electronic Resource

1432-1866

Springer Online Journal Archives 1860-2000

Geosciences

Abstract Platinum group elements (PGE) are strategic materials because 96–99% of the world production is derived from just five mining districts and because they cannot be replaced as catalysts in many chemical processes. In order to lessen the strategic character of PGE, both conventional deposits and unconventional PGE mineralizations were investigated in an attempt to locate viable deposits which would diversify the supplier base. In the Great Dyke, conventional PGE mineralization occurs in the form of pristine sulfide ores mined underground and oxidic surface ores. New observations such as bimodal distributions of the PGE in the Main Sulfide Zone (MSZ), elevated Pt/Pd ratios in the oxidized MSZ compared to the sulfidic part and distinct differences between the platinum group mineral (PGM) assemblages of the MSZ and stream sediments of adjacent rivers emphasize the fact that even though the Great Dyke seems to be the second or third largest PGE occurrence in the world, the complicated PGE distributions and supergene redistributions should be kept in mind during planning and mine operation. Investigations of unconventional PGE occurrences in ophiolites, Alaskan-type intrusions, porphyry copper deposits and in the Kupferschiefer show that economically exploitable PGE concentrations can be expected in a broader variety of host rocks than considered favourable in the past. In the Albanian Mirdita ophiolite average contents of 860 ppb Pt and 60 ppb Pd were detected. Flotation concentrates of porphyry copper deposits, for example from Mamut, Malaysia, Santo Tomas, Philippines, Elacite, Bulgaria, and Ok Tedi, Papua New Guinea, contain between 827 and 1860 ppb Pd + Pt. In selected profiles of the Polish Kupferschiefer average contents of 255 ppb Pt, 94 ppb Pd, 2.4 ppm Au and 13.0 ppm Ag were analysed. The distribution of the PGE resources in the world and the annual production rates, however, underline the fact that the chances for a significant change in the supplier base are relatively low. The Bushveld Complex will remain the largest producer, followed by Noril'sk-Talnakh, Sudbury and Stillwater. If the operations in the Great Dyke reach their planned capacities, the Great Dyke will rank in third place among the PGE-producing deposits in the world.

Electronic Resource

1432-2242

Glycine max ; Plant breeding ; Selection pressure

Springer Online Journal Archives 1860-2000

Biology

Abstract Theory predicts that selection for adaptability during the short term also favors selection for a reduced recombination rate in the population. The objective of this study was to test whether the cyclic short-term selection which has taken place in soybean breeding programs in the USA since the introduction of the crop has measurably reduced recombination frequencies. Thirteen soybean varieties separated into four different release periods (prior to 1940, 1940–1954, 1955–1969, after 1970) were evaluated for their recombination frequencies within three locus pairs. Recombination frequencies among the individual varieties ranged from 7.6 to 24.1 % at thep 1 r locus pair, from 20.9 to 30.1 % at thelnp 2 locus pair, and from 28.7 to 41.6% at thedt 1 l 1 locus pair. Recombination frequencies were significantly different among varieties within a release period for thep 1 r andlnp 2 locus pairs, but recombination frequencies did not differ among release periods for any locus pair. Thus, apparently, plant breeders have developed soybean varieties with improved adaptation without influencing recombination rates.

Electronic Resource

1432-2242

Medicago sativa L. ; 2n gametes ; Tissue culture ; Chromosome doubling

Springer Online Journal Archives 1860-2000

Biology

Summary Tetraploid alfalfa (Medicago sativa L.) clones were derived from the same diploid genetic background by four different methods. A phenotypically superior clone was selected from each method and compared for herbage yield and fertility. The four methods and their best clones were: a) In vitro somatic chromosome doubling of one diploid hybrid (HG2-4x); b) selection within a two allele tetraploid synthetic population derived from HG2-4x (HAG); c) somaclonal variant selection from cell suspension culture of the diploid hybrid (NS1); and d) sexual polyploidization of a sibling hybrid (HXG). Clones HG2-4x, HAG, and NS1 were likely diallelic or monoallelic at all loci. Clone HXG was probably tetrallelic or triallelic at most loci. Experiments measured fertility, clonal herbage yield, and herbage yield of test cross progeny for each selected clone. Fertility rankings were HXG = HAG 〉 NS1 〉 HG2-4x. Clonal herbage yield rankings were HXG = HAG 〉 NS1 〉 HG2-4x. Test cross progeny herbage yield rankings varied depending on the tester, but, in general, HXG ≧ HAG ≧ NS1 HG2-4x. Overall the best clones from the sexual methods exceeded the best somaclonal variant which, in turn, was better than the chromosome doubled clone.

Electronic Resource

1432-2242

Crossing-over ; Testcross ; Corn

Springer Online Journal Archives 1860-2000

Biology

Abstract Variability in recombination frequency was reported in the Iowa Stiff Stalk Synthetic. The objectives of the present research were to verify the differences in recombination frequency among individuals in the Iowa Stiff Stalk Synthetic maize population and to determine if the recombination frequency differences persisted among the S1 progeny. Testcrosses to measure male recombination frequency on three chromosomes (4, su1-c2; 5, a2-bt1-pr1; 9, sh1-bz1-wx1) were repeated for eight S0 individuals. Recombination frequencies were repeatably divergent among those individuals which were selected based on high or low recombination frequencies on specific chromosomes. Individuals which had been selected for long and short total map distances across the three chromosome regions produced repeatably divergent recombination frequencies only at the su1-c2 region. The recombination frequencies of the S1 lines, derived from the S0 individuals which had the most divergent recombination frequencies on a single chromosome, were significantly different. The broadsense heritability estimates derived from the regression of six S1 lines on six S0 individuals ranged from 0.69 to 0.20 for the five chromosome regions. We conclude that genetic differences for recombination frequency exist in this population and that modification by selection should be possible.

Electronic Resource

1432-2242

Crossing-over ; Testcross ; Quantitative inheritance

Springer Online Journal Archives 1860-2000

Biology

Abstract Variability in recombination frequency has been reported in several plant populations. The objectives of the present research were to establish the range in variability in recombination among genotypes in the important corn population Iowa Stiff Stalk Synthetic and to identify individual genotypes which produced increased or decreased recombination frequencies. Approximately 150 individual S0 plants were testcrossed to measure male recombination frequency on three chromosomes: 4, sul-c2; 5, a2-btl-pr1; and 9, sh1-bz1-wx1. Although the variance component for individuals accounted for only 20–33% of the total variation, highly significant variability among individuals was present at all chromosome regions. Thus the environmental effects did not prevent measurement of differences between S0 individuals. At each chromosome region, individual genotypes with recombination frequencies at least two standard deviations above or below the population mean were isolated. Reports in the literature suggest that the variability reported here for the BSSS population should be representative of that present in other corn breeding populations. Recombination frequencies were positively correlated between adjacent regions of chromosome 9 and also between adjacent regions of chromosome 5. Recombination frequencies were positively correlated between both regions on chromosome 5 with the su1-c2 region of chromosome 4. Negative correlations were observed between chromosome 9 recombination and recombination in each region of chromosomes 4 and 5. Thus rankings of S0 individual recombination frequencies were not consistent for all three chromosomes.

Electronic Resource

0016-7835

Key words Bohemian massif ; Teplá-Barrandian ; Hoher Bogen ; Ocean floor basalt ; Variscan metamorphism ; High grade

Springer Online Journal Archives 1860-2000

Geosciences

Abstract At its southern margin along the Hoher Bogen mountain, the Teplá-Barrandian (Bohemian massif, Central Europe) is made up of a 1- to 4-km wide belt of amphibolites. An upper amphibolite/lower granulite facies Variscan metamorphism has brought forth coarse-grained, weakly foliated rocks with hbl+pl±cpx±opx±grt parageneses. Since the beginning of this century, these rocks, together with fine-grained or mylonitized amphibolites, have been regarded as metamorphic gabbros (gabbro amphibolites) of the Neukirchen-Kdyne igneous complex. Relics of magmatic textures, however, cannot be found anywhere. The amphibolites are therefore reinterpreted as metamorphic basalts. The Hoher Bogen amphibolites (HBA) derive from N-type MORB. The most primitive samples have Mg#s between 60 and 65. Locally occurring (garnet-)hornblendites and leucodioritic mobilisates are the products of partial melting of amphibolites during the Variscan metamorphism and do not belong to the primary magmatic rock association. Ultramafic rocks are tectonically emplaced between the HBA belt and the metapelitic rocks of the Moldanubian. At the very least, the metapyroxenites among them seem to have a cumulus origin. Together with the ultramafic rocks, the HBA belt may be regarded as a metaophiolite, comparable to the Mariánské Lazne complex. The reinterpretation of the former "gabbro amphibolites" as a metaophiolite has consequences for the geology of the Teplá-Barrandian: the size of the Neukirchen-Kdyne igneous complex is reduced. The HBA belt is a piece of oceanic crust which is possibly younger than the Precambrian metasedimentary/metavolcanic country rock of the Neukirchen-Kdyne igneous complex.

Electronic Resource

1573-7284

Cryptococcus neoformans var. gattii ; Ecology

Springer Online Journal Archives 1860-2000

Medicine

Abstract Environmental isolations have established that Cryptococcus neoformans var. gattii serotype B appears to have a specific ecological association with Eucalyptus camaldulensis. The global distribution of the tree appears to correspond to the epidemiologic distribution of cryptococcosis caused by C. neoformans var. gattii. The epidemiology of cryptococcosis can primarily be explained by exposure to an infective aerosolized inoculum, such as basidiospores released from specific host plants and/or desiccated blastoconidia (yeast cells) disseminated from accumulations of dried pigeon dung. The ecology of C. neoformans still remains largely unresolved, studies on the host-parasite interaction between serotype B and E. camaldulensis are still in progress, and extensive environmental searches are now underway to determine the natural habitats of serotypes A, C and D.

Electronic Resource

1573-0662

radicals ; troposphere ; modelling ; yield measurements

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract Daily variations of the hydroxyl radical concentration have been measured during a campaign at the Weybourne Atmospheric Observatory (WAO) in June 1995. These measurements are compared with box model calculations, based on a slightly modified, second generation Regional Acid Deposition Model (RADM2). Results from eight days of the comparison are presented. A detailed analysis and discussion of the different source and sink terms is given for two days: Julian Day (JD) 170 (19 June, and 178 (27 June). In both cases excellent agreement between the measurements and the calculation is obtained, indicating that the model describes the OH chemistry sufficiently well. Furthermore, the analysis of these days demonstrate that JD 170 is dominated by the NOx catalysed OH production, whereas JD 178 is influenced by OH formation via ozone photolysis.

Electronic Resource

1618-2650

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Electronic Resource

0193-7197

Chemistry ; Chemical Engineering

Wiley InterScience Backfile Collection 1832-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Process Engineering, Biotechnology, Nutrition Technology

Europe has experienced phenomenal growth in the market share of rigid vinyl windows. The American market has shown intensified interest in dark brown rigid vinyl windows. European experience with these pigmentation systems provides a useful data base for designing these dark brown shades suitable for use in North American climatic conditions. Criteria for pigment selection are discussed, including the suitability of both organic and inorganic pigments. Test data are provided for selected pigment systems to show their suitability with regard to several application parameters. The contribution of other additives to appearance retention of colored rigid PVC is discussed. Typical formulations are presented in detail.

3 Ill.

Electronic Resource