Dioxygen Activation Kinetics over Distinct Cu Site Types in Cu-Chabazite Zeolites

ACS Catalysis ◽  
2021 ◽  
pp. 11873-11884
Author(s):  
Daniel T. Bregante ◽  
Laura N. Wilcox ◽  
Changming Liu ◽  
Christopher Paolucci ◽  
Rajamani Gounder ◽  
...  
Author(s):  
Petar Halachev ◽  
Victoria Radeva ◽  
Albena Nikiforova ◽  
Miglena Veneva

This report is dedicated to the role of the web site as an important tool for presenting business on the Internet. Classification of site types has been made in terms of their application in the business and the types of structures in their construction. The Models of the Life Cycle for designing business websites are analyzed and are outlined their strengths and weaknesses. The stages in the design, construction, commissioning, and maintenance of a business website are distinguished and the activities and requirements of each stage are specified.


The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.


2009 ◽  
Vol 89 (1) ◽  
pp. 67-79 ◽  
Author(s):  
Dave M Morris

The current study was conducted to quantify and compare dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) fluxes through black-spruce-dominated forests, to compare the source/sink characteristics of sphagnum- versus feathermoss-dominated forest floors, and to identify changes in DOC and DON flow patterns occurring as a result of clearcut harvesting. After 2 yr of pre-harvest monitoring, replicated, experimental harvests of varying intensities of biomass removals were conducted followed by 4 yr of post-harvest sampling. Prior to harvest, the upland site type, dominated by feathermoss, was a significant source of DOC and DON, whereas, the wet-sphagnum-dominated sites exported minor amounts of these solutes. After harvest, DOC and DON fluxes peaked in the second year, but then dropped off significantly to at or below pre-harvest levels. On the upland site type, chipper debris appeared to be a major source of DOC and DON generating fluxes well above the pre-harvest levels. On the wetter site types, it appeared that microclimate differences between harvest treatments had a stronger influence on DOC and DON production than did the amount or type of harvest residue. Full-tree harvesting did not significantly alter the production of DOC and DON when compared with stem-only harvesting on the sites included in this study. Key words: DOC, DON, forest floor leachate, black spruce, harvesting response


2016 ◽  
Vol 147 (6) ◽  
pp. 437-449 ◽  
Author(s):  
Petronel Tuluc ◽  
Bruno Benedetti ◽  
Pierre Coste de Bagneaux ◽  
Manfred Grabner ◽  
Bernhard E. Flucher

Alternative splicing of the skeletal muscle CaV1.1 voltage-gated calcium channel gives rise to two channel variants with very different gating properties. The currents of both channels activate slowly; however, insertion of exon 29 in the adult splice variant CaV1.1a causes an ∼30-mV right shift in the voltage dependence of activation. Existing evidence suggests that the S3–S4 linker in repeat IV (containing exon 29) regulates voltage sensitivity in this voltage-sensing domain (VSD) by modulating interactions between the adjacent transmembrane segments IVS3 and IVS4. However, activation kinetics are thought to be determined by corresponding structures in repeat I. Here, we use patch-clamp analysis of dysgenic (CaV1.1 null) myotubes reconstituted with CaV1.1 mutants and chimeras to identify the specific roles of these regions in regulating channel gating properties. Using site-directed mutagenesis, we demonstrate that the structure and/or hydrophobicity of the IVS3–S4 linker is critical for regulating voltage sensitivity in the IV VSD, but by itself cannot modulate voltage sensitivity in the I VSD. Swapping sequence domains between the I and the IV VSDs reveals that IVS4 plus the IVS3–S4 linker is sufficient to confer CaV1.1a-like voltage dependence to the I VSD and that the IS3–S4 linker plus IS4 is sufficient to transfer CaV1.1e-like voltage dependence to the IV VSD. Any mismatch of transmembrane helices S3 and S4 from the I and IV VSDs causes a right shift of voltage sensitivity, indicating that regulation of voltage sensitivity by the IVS3–S4 linker requires specific interaction of IVS4 with its corresponding IVS3 segment. In contrast, slow current kinetics are perturbed by any heterologous sequences inserted into the I VSD and cannot be transferred by moving VSD I sequences to VSD IV. Thus, CaV1.1 calcium channels are organized in a modular manner, and control of voltage sensitivity and activation kinetics is accomplished by specific molecular mechanisms within the IV and I VSDs, respectively.


2017 ◽  
Vol 56 (4) ◽  
pp. 2145-2152 ◽  
Author(s):  
Kothanda Rama Pichaandi ◽  
Lara Kabalan ◽  
Hashem Amini ◽  
Guanghui Zhang ◽  
Hanyu Zhu ◽  
...  
Keyword(s):  

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