712 research outputs found
A Phenomenological Exploration of Beginning Counselor Educatorsâ Experiences Developing a Research Agenda
Hermeneutic, phenomenological methodology was used to explore experiences developing a research agenda for five beginning counselor educators. Through in-depth, open-ended interviews, experiences included (a) balance, (b) isolation, and (c) evaluation while references to trusting relationships were manifest across all themes. Recommendations for counselor educators spanning the profession are provided
Synthesis and post-synthetic modification of amine-, alkyne-, azide- and nitro-functionalized metal-organic frameworks based on DUT-5
Functionalized 4,4âČ-biphenyldicarboxylic acid molecules with additional amine, alkyne, azide or nitro groups were prepared and applied in the synthesis of novel metal-organic frameworks and mixed-linker metal-organic frameworks isoreticular to DUT-5. The properties of the frameworks could be tuned by varying the number of functional groups in the materials and the amine groups were employed in post-synthetic modification reactions without changing the framework structure or significantly decreasing the porosity of the materials. © The Royal Society of Chemistry 2015
Post-synthetic Modification of DUT-5-based Metal Organic Frameworks for the Generation of Single-site Catalysts and their Application in Selective Epoxidation Reactions
New singleâsite catalysts based on mixedâlinker metalâorganic frameworks with DUTâ5 structure, which contain immobilized Co2+, Mn2+ and Mn3+ complexes, have successfully been synthesized via postâsynthetic modification. 2,2ââBipyridineâ5,5ââdicarboxylate linkers were directly metalated, while 2âaminoâ4,4ââbiphenyldicarboxylate linkers were postâsynthetically modified by their conversion to Schiffâbase ligands and a subsequent immobilization of the metal complexes. The resulting materials were used as catalysts in the selective epoxidation of transâstilbene and the activities and selectivities of the different catalysts were compared. The influence of various reaction parameters on conversion, yield and selectivity were investigated. Very low catalyst amounts of 0.02â
molâ% were sufficient to obtain a high conversion of transâstilbene using molecular oxygen from air as the oxidant. For cobaltâcontaining MOF catalysts, conversions up to 90â% were observed and, thus, they were more active than their manganeseâcontaining counterparts. Recycling experiments and hot filtration tests proved that the reactions were mainly catalyzed via heterogeneous pathways
Experimental Evidence for the Incorporation of Two Metals at Equivalent Lattice Positions in Mixed-Metal MetalâOrganic Frameworks
Metalâorganic frameworks containing multiple metals distributed over crystallographically equivalent framework positions (mixedâmetal MOFs) represent an interesting class of materials, since the close vicinity of isolated metal centers often gives rise to synergistic effects. However, appropriate characterization techniques for detailed investigations of these mixedâmetal metalâorganic framework materials, particularly addressing the distribution of metals within the lattice, are rarely available. The synthesis of mixedâmetal FeCuBTC materials in direct syntheses proved to be difficult and only a thorough characterization using various techniques, like powder Xâray diffraction, Xâray absorption spectroscopy and electron paramagnetic resonance spectroscopy, unambiguously evidenced the formation of a mixedâmetal FeCuBTC material with HKUSTâ1 structure, which contained bimetallic FeâCu paddlewheels as well as monometallic CuâCu and FeâFe units under optimized synthesis conditions. The inâdepth characterization showed that other synthetic procedures led to impurities, which contained the majority of the applied iron and were impossible or difficult to identify using solely standard characterization techniques. Therefore, this study shows the necessity to characterize mixedâmetal MOFs extensively to unambiguously prove the incorporation of both metals at the desired positions. The controlled positioning of metal centers in mixedâmetal metalâorganic framework materials and the thorough characterization thereof is particularly important to derive structureâproperty or structureâactivity correlations
A Polymerase-chain-reaction Assay for the Specific Identification of Transcripts Encoded by Individual Carcinoembryonic Antigen (CEA)-gene-family Members
Carcinoembryonic antigen (CEA) is a tumor marker that belongs to a family of closely related molecules with variable expression patterns. We have developed sets of oligonucleotide primers for the specific amplification of transcripts from individual CEA-family members using the reverse transcriptase/ polymerase chain reaction (RT/PCR). Specific primer sets were designed for CEA, non-specific cross-reacting antigen (NCA), biliary glycoprotein (BGP), carcinoembryonic antigen gene-family members 1, 6 and 7 (CGMI, CGM6 and CGM7), and one set for all pregnancy-specific glycoprotein (PSG) transcripts. Primers were first tested for their specificity against individual cDNA clones and product-hybridization with internal, transcript-specific oligonucleotides. Total RNA from 12 brain and 63 gynecological tumors were then tested for expression of CEA-related transcripts. None were found in tumors located in the brain, including various mesenchymal and neuro-epithelial tumors. CEA and NCA transcripts were, however, present in an adenocarcinoma located in the nasal sinuses. In ovarian mucinous adenocarcinomas, we always found co-expression of CEA and NCA transcripts, and occasionally BGP mRNA. CEA-related transcripts were also found in some serous, endometrioid and clear-cell ovarian carcinomas. CEA, NCA and BGP transcripts were present in endometrial carcinomas of the uterus and cervical carcinomas, whereas uterine leiomyomas were completely negative. No transcripts were found from CGM 1, CGM6, CGM7 or from PSG genes in any of the tumors tested. The PCR data were compared with immunohistochemical investigations of ovarian tumors at the protein level using CEA (26/3/13)-, NCA-50/90 (9A6FR) and NCA-95 (80H3)-specific monoclonal antibodies
Irreversible impacts of heat on the emissions of monoterpenes, sesquiterpenes, phenolic BVOC and green leaf volatiles from several tree species
Climate change will induce extended heat waves to parts of the vegetation more frequently. High temperatures may act as stress (thermal stress) on plants changing emissions of biogenic volatile organic compounds (BVOCs). As BVOCs impact the atmospheric oxidation cycle and aerosol formation, it is important to explore possible alterations of BVOC emissions under high temperature conditions. Applying heat to European beech, Palestine oak, Scots pine, and Norway spruce in a laboratory setup either caused the well-known exponential increases of BVOC emissions or induced irreversible changes of BVOC emissions. Considering only irreversible changes of BVOC emissions as stress impacts, we found that high temperatures decreased the <i>de novo</i> emissions of monoterpenes, sesquiterpenes and phenolic BVOC. This behaviour was independent of the tree species and whether the <i>de novo</i> emissions were constitutive or induced by biotic stress. <br><br> In contrast, application of thermal stress to conifers amplified the release of monoterpenes stored in resin ducts of conifers and induced emissions of green leaf volatiles. In particular during insect attack on conifers, the plants showed <i>de novo</i> emissions of sesquiterpenes and phenolic BVOCs, which exceeded constitutive monoterpene emissions from pools. The heat-induced decrease of <i>de novo</i> emissions was larger than the increased monoterpene release caused by damage of resin ducts. For insect-infested conifers the net effect of thermal stress on BVOC emissions could be an overall decrease. <br><br> Global change-induced heat waves may put hard thermal stress on plants. If so, we project that BVOC emissions increase is more than predicted by models only in areas predominantly covered with conifers that do not emit high amounts of sesquiterpenes and phenolic BVOCs. Otherwise overall effects of high temperature stress will be lower increases of BVOC emissions than predicted by algorithms that do not consider stress impacts
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