Search Results - (Author, Cooperation:Stoecklin)

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Calculations of rate coefficients for the fast reaction of a structureless ion with a dipolar linear molecule in a 2Π electronic state are presented. The rotationally adiabatic capture theory is used together with a simple classical electrostatic potential. An analytical formula is derived for the rate coefficient in the low temperature limit. The reaction of H+3 with OH(X 2Π) is taken as an example. For temperatures less than 90 K, the rate coefficients differ from those calculated for molecules in 1Σ states. The most interesting new prediction is that the rate coefficient for the reaction of a 2Π polar molecule with an ion is proportional to T−1/2 for temperatures close to absolute zero.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

A calculation of the spectrum for the excitation of the van der Waals modes in ArHCN is reported. The coupled electron pair approximation is used to compute an ab initio potential energy surface for the interaction of Ar with rigid HCN. The rovibrational bound states for the complex are calculated using a variational coupled-basis set method in which a self-consistent field approach is used to optimize simultaneously the basis sets for both the intermolecular bending and stretching motions in the van der Waals molecule. The calculations are compared with experimental results, including a measurement of the infrared spectrum of ArHCN in the region of the CH stretching vibration. The calculations predict that several bending modes with frequencies less than 20 cm−1 should have excitation intensities large enough to be observed. These low frequency bending modes arise from the small rotational constant of the HCN molecule and are not due to special features of the Ar–HCN potential energy surface.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

Genetic variation within plant species in their response to elevated CO2 could be important for long-term changes in plant community composition because it allows for selection of responsive genotypes. Six years of in situ CO2 enrichment in a temperate grassland offered a unique opportunity to investigate such microevolutionary changes in a common herb of that plant community, Sanguisorba minor. Plants were grown from seeds collected at the end of a 6-year treatment in either ambient or elevated CO2. The resulting seedlings were grown under ambient or elevated CO2 and with or without interspecific competition by Bromus erectus in the greenhouse for two seasons. The effect of competition was included because we expected selection under elevated CO2 to favour increased competitive ability. Elevated CO2 in the greenhouse and competition both caused a significant reduction of the total dry mass in S. minor, by 12% and 40%, respectively, with no interaction between CO2 and competition. Genetic variation in all traits was substantial. Seed families responded differently to competition, but the family × greenhouse CO2 interaction was rather weak. There was no main effect of the field CO2 treatment on any parameter analysed in the greenhouse. However, the field CO2 treatment did significantly interact with the greenhouse CO2 treatment for the cumulative number of leaves, suggesting microevolutionary change in this plant trait. Families from ambient field CO2 produced fewer leaves under elevated greenhouse CO2, whereas families from elevated field CO2 retained constant number of leaves in either greenhouse CO2 treatment. Since this resulted in increased litter production of the families from elevated field CO2 under elevated greenhouse CO2, the microevolutionary response should, in turn, affect ecosystem functions through dry matter recycling.

Electronic Resource

1600-065X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary:  Gene-encoded anti-microbial peptides (AMPs) are widespread in nature, as they are synthesized by microorganisms as well as by multicellular organisms from both the vegetal and the animal kingdoms. These naturally occurring AMPs form a first line of host defense against pathogens and are involved in innate immunity. Depending on their tissue distribution, AMPs ensure either a systemic or a local protection of the organism against environmental pathogens. They are classified into three major groups: (i) peptides with an α-helical conformation (insect cecropins, magainins, etc.), (ii) cyclic and open-ended cyclic peptides with pairs of cysteine residues (defensins, protegrin, etc.), and (iii) peptides with an over-representation of some amino acids (proline rich, histidine rich, etc.). Most AMPs display hydrophobic and cationic properties, have a molecular mass below 25–30 kDa, and adopt an amphipathic structure (α-helix, β-hairpin-like β-sheet, β-sheet, or α-helix/β-sheet mixed structures) that is believed to be essential to their anti-microbial action. Interestingly, in recent years, a series of novel AMPs have been discovered as processed forms of large proteins. Despite the extreme diversity in their primary and secondary structures, all natural AMPs have the in vitro particularity to affect a large number of microorganisms (bacteria, fungi, yeast, virus, etc.) with identical or complementary activity spectra. This review focuses on AMPs forming α-helices, β-hairpin-like β-sheets, β-sheets, or α-helix/β-sheet mixed structures from invertebrate and vertebrate origins. These molecules show some promise for therapeutic use.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

We investigated the responses of model calcareous grassland communities to three CO2concentrations: 330, 500, and 660 μL L-1, The communities were composed of six species, Bromus erectus Hudson, Festuca ovina L., Prunella vulgaris L., Prunella grandiflora (L.) Scholler, Hieracium pilosella L., and Trifolium repens L., that are native to the calcareous grasslands of Europe. Genotypic variation in CO2 response was studied in Bromus erectus and Festuca ovina. Plants were harvested after c. 126 days of growth. We found that:〈list xml:id="l1" style="custom"〉At the community level, there were marginally significant (0.1≥P 〉 0.05) increases in leaf and litter dry weight with increasing CO2 concentration.There were significant differences between species in CO2 response, including both negative and positive responses. Prunella vulgaris had a significant negative response; Hieraciunt pilosella and Festuca ovina had significant positive responses; Prunella grandiflora had a marginally significant positive response; and Bromus erectus and Trifotium repens did not have significant responses.There was significant variation among genotypes in the response to elevated CO2 in Bromus erectus, but not in Festuca ovina.Based on the observed species- and genotype-level variation in CO2 response of calcareous grassland plants in this and other studies, we speculate that increasing atmospheric CO2 concentrations will alter community structure in calcareous grasslands.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

In diverse plant communities the relative contribution of species to community biomass may change considerably in response to elevated CO2. Along with species-specific biomass responses, reproduction is likely to change as well with increasing CO2 and might further accelerate shifts in species composition. Here, we ask if, after 5 years of CO2 exposure, seed production and seed quality in natural nutrient-poor calcareous grassland are affected by elevated CO2 (650 μL L−1 vs 360 μL L−1) and how this might affect long-term community dynamics. The effect of elevated CO2 on the number of flowering shoots (+ 24%, P 〈 0.01) and seeds (+ 29%, P = 0.06) at the community level was similar to above ground biomass responses in this year, suggesting that the overall allocation to sexual reproduction remained unchanged. Compared among functional groups of species we found a 42% increase in seed number (P 〈 0.01) of graminoids, a 33% increase (P = 0.07) in forbs, and no significant change in legumes (− 38%, n.s.) under elevated CO2. Large responses particularly of two graminoid species and smaller responses of many forb species summed up to the significant or marginally significant increase in seed number of graminoids and forbs, respectively. In several species the increase in seed number resulted both from an increase in flowering shoots and an increase in inflorescence size. In most species, seeds tended to be heavier (+ 12%, P 〈 0.01), and N-concentration of seeds was significantly reduced in eight out of 13 species. The fraction of germinating seeds did not differ between seeds produced in ambient and elevated CO2, but time to germination was significantly shortened in two species and prolonged in one species when seeds had been produced in elevated CO2. Results suggest that species specific increases in seed number and changes in seed quality will exert substantial cumulative effects on community composition in the long run.

Electronic Resource

0006-291X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] We used a COS cell co-transfection assay to study the hormonal synergism between prolactin and glucocorticoid hormones. COS cells do not express endogenous prolactin receptor or Stat5, a factor that confers the response to prolactin13"15, and only trace amounts of glucocorticoid receptor are ...

Electronic Resource

0006-291X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0301-0104

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

0301-0104

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

0166-1280

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

1435-702X

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1434-4726

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Das erstmals vonLermoyez beobachtete und seither nach ihm benannte Krankheitsbild gehört zum Formenkreis desMénièreschen Syndroms. Es setzt sich wie dieses aus den Symptomen Schwindel und Schwerhörigkeit zusammen. Im Gegensatz zum Ménière treten diese Symptome jedoch in umgekehrter Richtung auf und führen zur Normalhörigkeit. Außer nervös-funktionellen Störungen kommt als ursächlicher Faktor für beide Syndrome die Allergie in Frage. Ein eigener Fall vonLermoyezschem Syndrom wurde nach Angaben amerikanischer Autoren mit Histamininjektionen behandelt, was die Anfälle zum Verschwinden brachte und gleichzeitig zur Normalisierung des Gehörs führte.

Electronic Resource

1435-1463

Positron emission tomography ; (18F)methylspiperone ; clozapine ; haloperidol ; D2 dopamine receptors ; schizophrenia

Springer Online Journal Archives 1860-2000

Medicine

Summary Four schizophrenic patients were investigated with dynamic positron emission tomography (PET) using (18F)fluorodeoxyglucose (FDG) and (18F)methylspiperone (MSP) as tracers. Two schizophrenics were on haloperidol therapy at the time of MSP PET. The other two schizophrenics were treated with clozapine, in one of them MSP PET was carried out twice with different daily doses (100 mg and 450 mg respectively). Neuroleptic serum levels were measured in all patients. Results were compared with MSP PET of two drug-free male control subjects and with a previous fluoroethylspiperone (FESP) study of normals. Three hours after tracer injection specific binding of MSP was observed in the striatum in all cases. The striatum to cerebellum ratio was used to estimate the degree of neuroleptic-caused striatal D2 dopamine receptor occupancy. In the haloperidol treated patients MSP binding was significantly decreased, whereas in the clozapine treated patients striatum to cerebellum ratio was normal. Even the increase of clozapine dose in the same patient had no influence on this ratio. Despite the smaller number of patients the study shows for the first time in humans that striatal MSP binding reflects the different D2 dopamine receptor affinities of clozapine and haloperidol.

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1432-1440

Whipple's disease ; Chronic interstitial nephritis ; Granulomas ; Boeck's disease

Springer Online Journal Archives 1860-2000

Medicine

Summary Report is given on a 68-year-old man who suffered primarily from progressive weight loss and repeated episodes of fever and arthralgia. Later, liver dysfunction and renal insufficiency developed. Liver and kidney biopsics disclosed granulomatous hepatitis and nephritis. Because of the morphologic and clinical findings, the diagnosis of Boeck's disease was made. Shortly before death, diarrhea developed. Autopsy revealed a massive systemic involvement in Whipple's disease proven by light and electron microscopy and immunofluorescence. Tuberculoid and epitheloid cell granulomas and isolated giant cells were found in addition to the biopsy findings in skeleton muscles, the small intestine, lymphnodes and bronchi. At autopsy, the kidney showed chronic interstitial nephritis. The literature of kidney involvement in Whipple's disease is reviewed. This is the first case with granulomatous interstitial nephritis and chronic renal insufficiency in an inadequately treated Whipple's disease.

Electronic Resource

1432-1939

Key words Calcareous grassland ; Conservation ; Local extinction ; Seed bank ; Seed longevity

Springer Online Journal Archives 1860-2000

Biology

Abstract We investigated whether plant species with longer-lived seeds in the soil had lower rates of local extinction between 1950 and 1985 than species with shorter-lived seeds in 26 intact remnants of extensively used calcareous grasslands. In a previous study we had found higher rates of local extinction for smaller populations, for species with shorter life cycles, and for species with higher habitat specificity. We compiled information on seed longevity from recent literature. Seed longevity had a highly significant effect on the rate of population extinction. Rates of local extinction were lower for species with seed longevity 〉5 years (33.8%; 31 species) compared with species with shorter-lived seeds (1–5 years: 60.7%, 46 species; 〈1 year: 58.5%, 81 species). The integration of seed longevity into our analysis did not change our previous conclusions on the dependence of local extinction rates on habitat specificity and on life form. Species in our data set with higher habitat specificity tended to have shorter-lived seeds than species with lower habitat specificity. Thus, most characteristic species of calcareous grassland do not persist in the seed bank and can not rely on this mechanism as a buffer against local extinction.

Electronic Resource

1432-1939

Key words Carbon dioxide ; Diversity ; Biomass ; Fertilization ; Legumes

Springer Online Journal Archives 1860-2000

Biology

Abstract We investigated the effects of elevated CO2 (600 μl l−1 vs 350 μl l−1) and phosphorus supply (1 g P m−2 year−1 vs unfertilized) on intact monoliths from species-rich calcareous grassland in a greenhouse. Aboveground community dry mass remained almost unaffected by elevated CO2 in the first year (+6%, n.s.), but was significantly stimulated by CO2 enrichment in year two (+26%, P〈0.01). Among functional groups, only graminoids contributed significantly to this increase. The effect of phosphorus alone on community biomass was small in both years and marginally significant only when analyzed with MANOVA (+6% in year one, +9% in year two, 0.1 ≥P 〉 0.05). Belowground biomass and stubble after two seasons were not different in elevated CO2 and when P was added. The small initial increase in aboveground community biomass under elevated CO2 is explained by the fact that some species, in particular Carex flacca, responded very positively right from the beginning, while others, especially the dominant Bromus erectus, responded negatively to CO2 enrichment. Shifts in community composition towards more responsive species explain the much larger CO2 response in the second year. These shifts, i.e., a decline in xerophytic elements (B. erectus) and an increase in mesophytic grasses and legumes occurred independently of treatments in all monoliths but were accelerated significantly by elevated CO2. The difference in average biomass production at elevated compared to ambient CO2 was higher when P was supplied (at the community level the CO2 response was enhanced from 20% to 33% when P was added, in graminoids from 17% to 27%, in legumes from 4% to 60%, and in C. flacca from 120% to 298% by year two). Based on observations in this and similar studies, we suggest that interactions between CO2 concentration, species presence, and nutrient availability will govern community responses to elevated CO2.

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1432-1939

Key words Dinitrogen fixation ; Plant functional types ; legumes ; Nutrient limitation ; Phosphorus

Springer Online Journal Archives 1860-2000

Biology

Abstract Plant nutrient responses to 4 years of CO2 enrichment were investigated in situ in calcareous grassland. Beginning in year 2, plant aboveground C:N ratios were increased by 9% to 22% at elevated CO2 (P 〈 0.01), depending on year. Total amounts of N removed in biomass harvests during the first 4 years were not affected by elevated CO2 (19.9 ± 1.3 and 21.1 ± 1.3 g N m−2 at ambient and elevated CO2), indicating that the observed plant biomass increases were solely attained by dilution of nutrients. Total aboveground P and tissue N:P ratios also were not altered by CO2 enrichment (12.5 ± 2 g N g−1 P in both treatments). In contrast to non-legumes (〉98% of community aboveground biomass), legume C/N was not reduced at elevated CO2 and legume N:P was slightly increased. We attribute the less reduced N concentration in legumes at elevated CO2 to the fact that virtually all legume N originated from symbiotic N2 fixation (%Ndfa ≈ 90%), and thus legume growth was not limited by soil N. While total plant N was not affected by elevated CO2, microbial N pools increased by +18% under CO2 enrichment (P = 0.04) and plant available soil N decreased. Hence, there was a net increase in the overall biotic N pool, largely due increases in the microbial N pool. In order to assess the effects of legumes for ecosystem CO2 responses and to estimate the degree to which plant growth was P-limited, two greenhouse experiments were conducted, using firstly undisturbed grassland monoliths from the field site, and secondly designed `microcosm' communities on natural soil. Half the microcosms were planted with legumes and half were planted without. Both monoliths and microcosms were exposed to elevated CO2 and P fertilization in a factored design. After two seasons, plant N pools in both unfertilized monoliths and microcosm communities were unaffected by CO2 enrichment, similar to what was found in the field. However, when P was added total plant N pools increased at elevated CO2. This community-level effect originated almost solely from legume stimulation. The results suggest a complex interaction between atmospheric CO2 concentrations, N and P supply. Overall ecosystem productivity is N-limited, whereas CO2 effects on legume growth and their N2 fixation are limited by P.

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1432-1920

Positron emission tomography ; [11C]methyl-D-glucose ; Functional activity, decreased ; Visual pathway, interruption

Springer Online Journal Archives 1860-2000

Medicine

Summary A hemorrhagic infarction which caused left hemiparesis and homonymous hemianopia was demonstrated as a hypodense lesion on the first CT; 2 weeks later it was hyperdense and enhanced after injecting meglumine. Positron emission tomography with [11C]methyl-D-glucose also revealed the ischemic lesion, but also marked decrease of glucose uptake in the visual cortex, which indicated decreased functional activity.

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