bluuebunny/crossref_metadata_2025_split huggingface dataset:
Titanium Complexes Stabilized by Bulky Electron‐Rich Aminopyridinates and Their Application in Ethylene and Styrene Polymerization
Authors: Hafeez Muhammad , Kretschmer Winfried P. , Kempe Rhett 
Published: November 2011

AbstractA series of electron‐rich aminopyridines with high electron density at the Npyridine atom (due to an electron‐donating mesomeric effect) was prepared by the Ni0/2,2′‐bipyridine‐catalyzed arylation of anilines, followed by an uncatalyzed amination reaction. Reacting 2,6‐dichloropyridine with 1 equiv. of aniline in the presence of the Ni0/2,2′‐bipyridine catalyst gave exclusively N‐(6‐chloropyridin‐2‐yl)aniline. Subsequent reaction with secondary alkylamines provided electron‐rich aminopyridines in which the lone pair of the RR′N substituent participates in the molecular π‐system. These aminopyridines react with [Et2NTiCl3] (Et = ethyl) and undergo amine elimination to form simultaneously the corresponding aminopyridinate (Ap) ligand‐stabilized titanium trichlorides [ApTiCl3] and Ap (diethylamido)titanium dichlorides [Ap(Et2N)TiCl2]. The reaction presumably proceeds via the reaction of the initially formed [ApTiCl3] with 2 equiv. of the prereleased diethylamine to give the [Ap(Et2N)TiCl2] complexes and diethylammonium chloride. Alternative selective synthetic routes for both sorts of complexes are also presented. These compounds were characterized by spectroscopic methods and X‐ray diffraction analysis (selected complexes). Furthermore, their behavior in ethylene and styrene polymerization reactions was explored. The complexes show high activity towards ethylene if activated with d‐MAO (‘‘dry” methylaluminoxane) but were almost inactive if d‐MAO was replaced with conventional MAO. The observed polyethylene (PE) product was analyzed by NMR spectroscopy and found to be fully saturated, indicating a chain transfer reaction to aluminum had occurred. Styrene waspolymerized in a highly syndiospecific fashion.
Roles of human sulfotransferases in genotoxicity of carcinogens using genetically engineered umu test strains
Authors: Oda Yoshimitsu , Zhang Yu , Buchinger Sebastian , Reifferscheid Georg , Yang Min 
Published: November 2011

AbstractHuman sulfotransferase (SULT) 1A1, 1A2, and 1A3 cDNA genes were subcloned separately into the pTrc99AKM vector. The generated plasmids were introduced into the Salmonella typhimurium
O‐acetyltransferase‐deficient strain NM6000 (TA1538/1,8‐DNP/pSK1002), resulting in the new strains NM7001, NM7002, and NM7003. We compared the sensitivities of these three strains with the parental strain NM7000 against 51 chemicals including aromatic amines, nitroarenes, alkenylbenzenes, estrogens‐like chemicals, and other compounds with and without S9 mix by making use of the umu test system that is based on the bacterial SOS induction. 2‐Amino‐6‐methyl‐dipyrido[1,2‐α:3′,2′‐d]imidazole, 3‐methoxy‐4‐aminoazobenzene, 3‐nitrobenzanthrone, 5‐nitroacenaphthene, and 3,9‐dinitrofluoranthene caused high genotoxicity in the NM7001 strain. The genotoxic effects of 2‐aminofluorene, 2‐acetylaminofluorene, 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine, 2‐nitrofluorene, 1‐nitropyrene, and 2‐nitropropane were stronger in the NM7002 strain compared with the NM7001 and NM7003 strains. Among the tested benzylic and allylic compounds, 1‐hydroxymethylpyrene was detected in the NM7001 strain with the highest sensitivity. Estragole and 1′‐hydroxysafrole exhibited strong genotoxicity in the NM7003 strain. The estrogen‐like chemicals such as bisphenol A, genistein, p,n‐nonylphenol, and 4‐hydroxytamoxifen were not detected as genotoxins in any strain used. Collectively, the present results suggest that the generated test strains are valuable tools in order to elucidate the role of SULT enzymes in the bioactivation of chemicals to environmental carcinogens. Environ. Mol. Mutagen. 2012. © 2011 Wiley Periodicals, Inc.
CD133 and CD44 are universally overexpressed in GIST and do not represent cancer stem cell markers
Authors: Chen Junwei , Guo Tianhua , Zhang Lei , Qin Li‐Xuan , Singer Samuel , Maki Robert G. , Taguchi Takahiro , DeMatteo Ronald , Besmer Peter , Antonescu Cristina R. 
Published: November 2011

AbstractAlthough imatinib mesylate has been a major breakthrough in the treatment of advanced gastrointestinal stromal tumors (GIST), complete responses are rare and most patients eventually develop resistance to the drug. Thus, the possibility of an imatinib‐insensitive cell subpopulation within GIST tumors, harboring stem cell characteristics, may be responsible for the clinical failures. However, the existence of a cancer stem cell component in GIST has not been yet established. This study was aimed to determine whether expression of commonly used stem cell markers in other malignancies, that is, CD133 and CD44, might identify cells with characteristics of cancer stem/progenitor cells in human GIST. CD133 and CD44 expression in GIST explants was analyzed by flow cytometry, immunofluorescence, and gene expression. Their transcription levels were correlated with clinical and molecular factors in a large, well‐annotated cohort of GIST patients. FACS sorted GIST cells based on CD133 and CD44 expression were isolated and used to assess phenotypic characteristics, ability to maintain their surface expression, sensitivity to imatinib, and expression signature. The enrichment in CD133/CD44 cells in the side population (SP) assay was also investigated. CD133 expression was consistently found in GIST. CD133− cells formed more colonies, were more invasive in a matrigel assay, and showed enrichment in the SP cells, compared to CD133+ cells. CD133 expression was also detected in the two imatinib‐sensitive GIST cell lines, while was absent in the imatinib‐resistant lines. Our results show that CD133 and CD44 are universally expressed in GIST, and may represent a lineage rather than a cancer stem cell marker. © 2011 Wiley Periodicals, Inc.
Neoplastic MiR‐17∼92 deregulation at a dna fragility motif (SIDD)
Authors: Schneider Björn , Nagel Stefan , Ehrentraut Stefan , Kaufmann Maren , Meyer Corinna , Geffers Robert , Drexler Hans G. , MacLeod Roderick A. F. 
Published: November 2011

AbstractChromosomal or mutational activation of BCL6 (at 3q27) typifies diffuse large B‐cell lymphoma (DLBCL) which in the germinal center subtype may be accompanied by focal amplification of chromosome band 13q31 effecting upregulation of miR‐17∼92. Using long distance inverse‐polymerase chain reaction, we mapped and sequenced six breakpoints of a complex BCL6 rearrangement t(3;13)(q27;q31)t(12;13)(p11;q31) in DLBCL cells, which places miR‐17∼92 antisense within the resulting ITPR2‐BCL6 chimeric fusion gene rearrangement. MiR‐17∼92 members were upregulated ∼15‐fold over controls in a copy number independent manner consistent with structural deregulation. MIR17HG and ITPR2‐BCL6 were, despite their close configuration, independently expressed, discounting antisense regulation. MIR17HG in t(3;13)t(12;13) cells proved highly responsive to treatment with histone deacetylase inhibitors implicating epigenetic deregulation, consistent with which increased histone‐H3 acetylation was detected by chromatin immunoprecipitation near the upstream MIR17HG breakpoint. Remarkably, 5/6 DNA breaks in the t(3;13)t(12;13) precisely cut at stress‐induced DNA duplex destabilization (SIDD) peaks reminiscent of chromosomal fragile sites, while the sixth lay 150 bp distant. Extended SIDD profiling showed that additional oncomiRs also map to SIDD peaks. Fluorescence in situ hybridization analysis showed that 11 of 52 (21%) leukemia‐lymphoma (L‐L) cell lines with 13q31 involvement bore structural rearrangements at/near MIR17HG associated with upregulation. As well as fueling genome instability, SIDD peaks mark regulatory nuclear‐scaffold matrix attachment regions open to nucleosomal acetylation. Collectively, our data indict a specific DNA instability motif (SIDD) in chromosome rearrangement, specifically alterations activating miR‐17∼92 epigenetically via promoter hyperacetylation, and supply a model for the clustering of oncomiRs near cancer breakpoints. © 2011 Wiley Periodicals, Inc.
Expression profiles of carcinosarcoma of the uterine corpus—are these similar to carcinoma or sarcoma?
Authors: Chiyoda Tatsuyuki , Tsuda Hiroshi , Tanaka Hideo , Kataoka Fumio , Nomura Hiroyuki , Nishimura Sadako , Takano Masashi , Susumu Nobuyuki , Saya Hideyuki , Aoki Daisuke 
Published: November 2011

AbstractUterine carcinosarcoma (CS) is usually classified as uterine endometrial carcinoma (EC). However, CS is more aggressive even compared with high grade EC. CS is also reported to undergo epithelial to mesenchymal transition (EMT). In this study, we compared the gene expression profiles of CS, EC, and uterine sarcoma (US) and evaluated the role of EMT and chromosomal aberrations in CS tumor formation. Frozen tissues of 46 patients (14 CS, 24 EC, and 8 US) were included. The similarity was examined by Gene Set Enrichment Analysis (GSEA), Fisher's exact test, and clustering using “intrinsic gene set”. We examined the expression of 39 EMT‐related genes and evaluated TGF‐beta signaling by phospho‐SMAD2/3 (p‐SMAD2/3) staining. Chromosomal regions differing between CS and EC were identified by chromosomal GSEA and comparative genomic hybridization (CGH) microarrays. Three statistical methods confirmed that CS resembled US rather than EC. Acquired markers of EMT were upregulated and attenuated markers of EMT were downregulated in CS. Immunohistochemistry showed that carcinomatous region of CS have higher expression of p‐SMAD2/3 than EC (P = 0.008). Chromosomal GSEA showed that genes located at 19q13 had higher expression in CS. Furthermore, CGH microarray indicated that the TGFB1 locus at 19q13.1 was amplified in 4 of 7 samples. Based on the expression profile, CS resembles US rather than EC. TGF‐beta signaling is activated in CS and chromosomal gains at 19q13, which includes the TGFB1 locus, suggest that this may contribute to high expression of TGF‐beta and thereby EMT phenotype of CS. © 2011 Wiley Periodicals, Inc.
The impact of pipe flow in riparian peat deposits on nitrate transport and removal
Authors: Hill Alan R. 
Published: November 2011

AbstractThe effect of preferential flow in soil pipes on nitrate retention in riparian zones is poorly understood. The characteristics of soil pipes and their influence on patterns of groundwater transport and nitrate dynamics were studied along four transects in a 1‐ to >3‐m deep layer of peat and marl overlying an oxic sand aquifer in a riparian zone in southern Ontario, Canada. The peat‐marl deposit, which consisted of several horizontal layers with large differences in bulk density, contained soil pipes that were generally 0.1 to 0.2 m in diameter and often extended vertically for 1 to >2 m. Springs that produced overland flow across the riparian area occurred at some sites where pipes extended to the peat surface. Concentrations of NO3−–N (20–30 mg L−1) and dissolved oxygen (DO) (4–6 mg L−1) observed in peat pipe systems and surface springs were similar to values in the underlying sand aquifer, indicating that preferential flow transported groundwater with limited nitrate depletion. Low NO3−–N concentrations of <5 mg L−1 and enriched δ15N values indicated that denitrification was restricted to small areas of the peat where pipes were absent. Groundwater DO concentrations declined rapidly to <2 mg L−1 in the peat matrix adjacent to pipes, whereas high NO3−–N concentrations of >15 mg L−1 extended over a larger zone. Low dissolved organic carbon values at these locations suggest that supplies of organic carbon were not sufficient to support high rates of denitrification, despite low DO conditions. These data indicate that it is important to develop a greater understanding of pipes in peat deposits, which function as sites where the transport of large fluxes of water with low biogeochemical reaction rates can limit the nitrate removal capacity of riparian zones. Copyright © 2011 John Wiley & Sons, Ltd.
Nutrient Fluxes from Land to Sea: Consequences of Future Scenarios on the Oder River Basin – Lagoon – Coastal Sea System
Authors: Krämer Inga , Hürdler Jens , Hirschfeld Jesko , Venohr Markus , Schernewski Gerald 
Published: November 2011

AbstractEutrophication management is still one of the major challenges in the Baltic Sea region. Intense transformation processes in several Baltic Sea states have led to drastic changes in e.g., landuse and thereby nutrient emissions and water quality. Several future development directions are possible. The Oder catchment – lagoon – coastal water system serves as a pilot study area, since it has a major influence on the nutrient loads into the Baltic Sea and about 90% of the catchment is located in Poland, a state with transitional economy. Different scenarios for landuse changes in the Oder catchment are developed and their consequences on nutrient emissions simulated. Next to politically induced changes of agricultural landuse in general, specific aspects such as cultivation of energy maize and increased animal stocks are considered. Nitrogen emissions are likely to increase due to agricultural landuse changes whereas phosphorus emissions will not change or even decrease according to the application of the EC‐Urban Waste Water Treatment Directive. Resulting nitrogen loads to the Oder Lagoon could increase up to 23%, phosphorus loads could decrease by 11% compared to 2005. These trends may lead to higher nitrogen availability compared to phosphorus at least in the Oder lagoon. Interannual differences in discharge also have profound effects on nutrient emissions. A good status of the Oder river basin – lagoon – coastal sea system according to EC‐Directives is not very likely to be achieved under the investigated circumstances. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of Recent Nutrient Emission Pathways, Resulting Surface Water Quality and Ecological Impacts under Extreme Continental Climate: The Kharaa River Basin (Mongolia)
Authors: Hofmann Jürgen , Hürdler Jens , Ibisch Ralf , Schaeffer Michael , Borchardt Dietrich 
Published: November 2011

AbstractThis paper presents primary research results on nutrient emissions, resulting water quality and ecological impacts of the Kharaa river basin (Mongolia) during a three‐year water resource management study. Based on surveillance data from Mongolian environmental authorities and a complementary own monitoring scheme we calculated nutrient emissions on a sub‐basin scale. Additionally, the ecological situation of fish fauna, macroinvertebrates and their habitats were investigated on selected river sections in order to link anthropogenic pressures, nutrient status and ecological impact.Although the headwaters of the Kharaa represent natural background conditions (total nitrogen (TN) 0.46 to 0.58 mg N L–1, total phosphorus (TP) 0.011 to 0.018 mg P L–1) and population densities within the catchment are very low (< 10 inhabitants km–2), the river basin is facing relatively high anthropogenic pressures on water quality in the middle and especially in the lower reaches (total nitrogen 1.50 to 1.52 mg N L–1, total phosphorus 0.18 to 0.26 mg P L–1). Nitrogen emissions into the Kharaa river basin were about 301 t N yr–1 for the time period 2006–2008. For phosphorus a total emission of 56 t P yr–1 was estimated. Main contributors are urban settlements with a high proportion of households without connection to wastewater treatment plants and, to a lesser extent, agricultural land‐use. These nutrient levels have a significant eutrophication potential in the Kharaa River and we observed functional shifts of the macroinvertebrates and fish fauna, while the drinking water abstraction through bank filtration showed no significant alteration of raw water quality. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Using Phytoplankton to Assess the Trophic Status of German Rivers
Authors: Mischke Ute , Venohr Markus , Behrendt Horst 
Published: November 2011

AbstractWe introduce the German multi‐metric assessment method PhytoFluss for large rivers, based on phytoplankton, which can be used to implement the European Water Framework Directive (WFD). First, we examined the response of chlorophyll a concentration to total phosphorus (TP) at 220 German river sites. Rivers could be assigned to one of four groups, based on the response curves: a) streams with high specific run‐off (Rhine, Danube) had the lowest yield of chlorophyll a per unit of TP, followed by b) low yield in small lowland rivers (Trave, Stepenitz), c) medium‐sized lowland rivers (Spree) and large central mountain rivers (Main) had intermediate yields of chlorophyll a, and d) streams with low specific run‐off (Elbe, Weser) and Baltic tributaries (Penne, Warnow) had the highest yield of chlorophyll a per unit of TP. To define the five trophic status classes of phytoplankton biomass according the WFD, the chlorophyll a boundaries were derived from these response curves at the 75% percentile level. All selected sites were pre‐classified with the combined trophic boundaries for TP and chlorophyll a to create the new four taxa composition metrics: The proportions of Chlorophytes, Cyanobacteria, or Pennales and of indicator taxa were selected as indicative parameters. When applying the final PhytoFluss method to 418 years of investigation from 150 German river sites, the percentages in each status according to the bio‐ component phytoplankton were: high 3%, good 19%, moderate 42%, poor 30%, and bad 5%. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling of Nutrient Emissions in River Systems – MONERIS – Methods and Background
Authors: Venohr Markus , Hirt Ulrike , Hofmann Jürgen , Opitz Dieter , Gericke Andreas , Wetzig Annett , Natho Stephanie , Neumann Franziska , Hürdler Jens , Matranga Marisa , Mahnkopf Judith , Gadegast Mathias , Behrendt Horst 
Published: November 2011

AbstractMONERIS is a semi‐empirical, conceptual model, which has gained international acceptance as a robust meso‐ to macro scale model for nutrient emissions. MONERIS is used to calculate nitrogen (N) and phosphorus (P) emissions into surface waters, in‐stream retention, and resulting loads, on a river catchment scale. This paper provides the first (i) comprehensive overview of the model structure (both the original elements and the new additions), (ii) depiction of the algorithms used for all pathways, and for retention in surface waters, and (iii) illustration of the monthly disaggregation of emissions and the implementation of measures. The model can be used for different climatic conditions, long term historical studies, and for future development scenarios. The minimum validated spatial resolution is 50 km2, with a temporal resolution of yearly or monthly time steps. The model considers seven emission pathways (atmospheric deposition on surface waters, overland flow, erosion, tile drainage, groundwater, emissions from sealed urban areas, and point sources), and six emission sources (natural background, fertilizer application, nitrogen atmospheric deposition on arable land and other areas, urban sources, and point sources); and these are calculated separately for different land‐uses. The pathway and source‐related approach is a prerequisite for the implementation of measures to reduce non‐point and point‐source emissions. Therefore, we have modified MONERIS by the addition of a “management alternative” tool which can identify the potential effectiveness of nutrient reduction measures. MONERIS is an appropriate tool for addressing the scientific and political aspects of river basin management in support of a good surface water quality. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the mode of action of the herbicides cinmethylin and 5‐benzyloxymethyl‐1, 2‐isoxazolines: putative inhibitors of plant tyrosine aminotransferase
Authors: Grossmann Klaus , Hutzler Johannes , Tresch Stefan , Christiansen Nicole , Looser Ralf , Ehrhardt Thomas 
Published: November 2011

AbstractBACKGROUND: The mode of action of the grass herbicides cinmethylin and 5‐benzyloxymethyl‐1,2‐isoxazolines substituted with methylthiophene (methiozolin) or pyridine (ISO1, ISO2) was investigated.RESULTS: Physiological profiling using a series of biotests and metabolic profiling in treated duckweed (Lemna paucicostata L.) suggested a common mode of action for the herbicides. Symptoms of growth inhibition and photobleaching of new fronds in Lemna were accompanied with metabolite changes indicating an upregulation of shikimate and tyrosine metabolism, paralleled by decreased plastoquinone and carotenoid synthesis. Supplying Lemna with 10 µM of 4‐hydroxyphenylpyruvate (4‐HPP) reversed phytotoxic effects of cinmethylin and isoxazolines to a great extent, whereas the addition of L‐tyrosine was ineffective. It was hypothesised that the herbicides block the conversion of tyrosine to 4‐HPP, catalysed by tyrosine aminotransferase (TAT), in the prenylquinone pathway which provides plastoquinone, a cofactor of phytoene desaturase in carotenoid synthesis. Accordingly, enhanced resistance to ISO1 treatment was observed in Arabidopsis thaliana L. mutants, which overexpress the yeast prephenate dehydrogenase in plastids as a TAT bypass. In addition, the herbicides were able to inhibit TAT7 activity in vitro for the recombinant enzyme of A. thaliana.CONCLUSION: The results suggest that TAT7 or another TAT isoenzyme is the putative target of the herbicides. Copyright © 2011 Society of Chemical Industry
Tropical transition of a Mediterranean storm by jet crossing
Authors: Chaboureau Jean‐Pierre , Pantillon Florian , Lambert Dominique , Richard Evelyne , Claud Chantal 
Published: November 2011

AbstractThe tropical transition of a Mediterranean storm that occurred on 26 September 2006 over southeastern Italy is investigated. The explosive development classified this cyclone as a bomb and its full‐tropospheric warm core as a tropical‐like storm or medicane. Forecasts at different scales were analysed to identify the key mechanisms in the explosive development of the medicane. At 108 h lead time, the European Centre for Medium‐Range Weather Forecasts (ECMWF) failed to predict the medicane and the associated upper‐level trough downstream of the ex‐tropical cyclone Helene during its extratropical transition. At shorter range, forecasts by both ECMWF and Action de Recherche Petite Echelle Grande Echelle (ARPEGE) increasingly improved with decreasing lead times. The depth of the medicane was missed, however, probably because of the too low resolution with respect to the 60 km diameter cyclone. Forecasts at kilometre scale were run using the mesoscale model Meso‐NH and verified against in situ and satellite observations. The Meso‐NH forecasts were found to be very sensitive to the initial conditions. Reduced static stability at the southern tip of the upper‐level trough determined the convective activity around the pre‐existing mesocyclone. The medicane was then formed only if enough vertically developed convection was further enhanced by the jet‐induced upward forcing. Otherwise, no tropical transition of the mesocyclone was predicted. This study shows the role of an upper‐level jet in explosively deepening a mesocyclone into a tropical storm. Copyright © 2011 Royal Meteorological Society