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1.
Over the past year, several significant developments have been made in the field of anion binding. The fundamental principles of molecular recognition are increasingly being better understood, and of particular interest are reports of several synthetic anion receptors able to perform their task in complex natural media. Additionally, macroscopic devices such as anion specific electrodes and membranes based on a molecular recognition approach are now being made. 相似文献
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The population dynamics of Heterodera glycines as influenced by alachlor, fenamiphos, and ethoprop alone and in herbicide-nematicide combinations were studied in the field. Numbers of H. glycines juveniles and eggs were higher at midseason and harvest where nematicides were applied. Fenamiphos alone or in combination with alachlor provided better control of H. glycines and greater seed yields than treatments with ethoprop. Numbers of H. glycines eggs at harvest in 1980 were positively correlated with numbers of juveniles at planting in 1981 and negatively related to seed yield in 1981. 相似文献
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Cornel Schmitt und Hans Stadler 《Journal of Ornithology》1918,66(2):220-234
Ohne ZusammenfassungIII.) Nachtigall, Kuckuck, Tannenmeise.S. Journ. f. Ornithologie 1917, Festschrift für Reichenow. 相似文献
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Food subsidies have the potential to modify ecosystems and affect the provision of goods and services. Predictable Anthropogenic Food Subsidies (PAFS) modify ecosystems by altering ecological processes and food webs. The global concern over the effects of PAFS in ecosystems has led to development of environmental policies aimed at curbing the production or ultimately banning of PAFS. However, the effects of reducing or banning PAFS are not known. We explore the consequences of PAFS removal in a marine ecosystem under two scenarios: 1) gradual reduction, or 2) an abrupt ban, using a mass balance model to test these hypotheses–The reduction or loss of PAFS will: i) modify trophic levels and food webs through effects on foraging by opportunistic species, ii) increase the resilience of opportunistic species to food shortages, and iii) modify predator–prey interactions through shifts in prey consumption. We found that PAFS lower the trophic levels of opportunistic scavengers and increase their food pathways. Scavengers are able to switch prey when PAFS are reduced gradually but they decline when PAFS are abruptly banned. PAFS reduction to a certain minimal level causes a drop in the ecosystem’s stability. We recommend gradual reduction of PAFS to a minimal level that would maintain the ecosystem’s stability and allow species exploiting PAFS to habituate to the food subsidy reduction. 相似文献
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Nikolas K. Haass D. Ripperger E. Wladykowski P. Dawson P. A. Gimotty C. Blome F. Fischer P. Schmage I. Moll Johanna M. Brandner 《Histochemistry and cell biology》2010,133(1):113-124
Melanoma depends on, interacts with and reacts to the stroma in which it is embedded, including fibroblasts, extracellular
matrix, endothelial cells and immune cells. However, the impact of melanoma on the epidermal tumor microenvironment—the multilayered
epithelium of the skin—is poorly understood. Gap junctions are essential for intercellular communication and involved in proliferation,
differentiation and homeostasis of keratinocytes. We have shown previously that the gap junction proteins connexin 26 and
30 (Cx26 and Cx30) are induced in the epidermal tumor microenvironment of skin cancers including melanoma. This study compares
the extent of Cx26, Cx30 and Cx43 expression in the epidermal microenvironment of melanocytic nevi and melanomas and its association
with melanoma thickness, proliferative index of the tumor and its microenvironment, and with 5-year metastasis and survival.
We found that induction of Cx26 and Cx30 cell–cell border expression in the epidermal tumor microenvironment correlates to
malignancy. Importantly, there was a significant correlation of tumor thickness with the vertical epidermal Cx26 and Cx30
expression pattern and the horizontal Cx26 dissemination. Furthermore, horizontal Cx26 expression correlated with metastasis.
Vertical epidermal expression patterns of Cx26 and Cx30 significantly correlated with the proliferative index in the epidermal
tumor microenvironment but not with the proliferative index in the tumor. In contrast, Cx43 did not correlate with malignancy,
thickness or proliferative index. In summary, here we show for the first time a significant association between the progression
of melanoma and alterations in its epithelial tumor microenvironment. 相似文献
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