5,857 research outputs found
Improvements in virological control among women conceiving on combination antiretroviral therapy in Western Europe.
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THE IDENTIFICATION OF NOVEL INORGANIC CARBON SENSITIVE ENZYMES
No full textAdenylyl cyclase catalyses the formation of the second messenger adenosine-3’, 5’-monophosphate from adenosine triphosphate, and is involved in a number of diverse signalling pathways in eukaryotes and prokaryotes. Adenylyl cyclases are diverse in their structure and biochemistry, and have been grouped into six distinct Classes (I–VI). The Class III cyclase homology domain comprises the majority of prokaryotic and eukaryotic adenylyl cyclases, and has been further divided into 4 sub-Classes (a-d) based on active site polymorphisms. A number of Class IIIb adenylyl cyclases display elevated catalytic activity in the presence of inorganic carbon. Whether a response to inorganic carbon can be observed in enzymes which do not possess a Class IIIb cyclase homology domain remains to be established.
Experiments were performed to investigate the response to inorganic carbon of a Class IIIa cyclase homology domain; mammalian transmembrane adenylyl cyclase. In vivo experiments demonstrated that the activity of mammalian transmembrane adenylyl cyclase was potentially regulated by inorganic carbon, and that this had a downstream effect on the cAMP response element binding protein. In vitro experiments performed on a transmembrane adenylyl cyclase demonstrated that the increase in activity in the presence of inorganic carbon occurred through an increase in kcat and increased metal affinity.
Experiments were performed to test the response to inorganic carbon of several enzymes that share a structurally similar active site with the adenylyl cyclases; the polymerase I family of prokaryotic DNA polymerases, the polymerase β family of DNA polymerases, and the guanylyl cyclases. Initial in vitro experiments performed on T7 RNA polymerase demonstrated a response to inorganic carbon, however, it was discovered that this was likely due to a non-specific effect of pH. It was shown that inorganic carbon increased assay pH over time, and this warranted a re-design of the in vitro assay used to test the response of an enzyme to inorganic carbon. This new in vitro assay methodology was used to re-test T7 RNA polymerase, as well as test DNA polymerase β and several guanylyl cyclase, and demonstrated that these enzymes were non-responsive to inorganic carbon.
Using this newly devised in vitro assay, experiments were performed to re-test the response of mammalian transmembrane adenylyl cyclase to inorganic carbon, and demonstrated that this enzyme was unlikely to be regulated by inorganic carbon. Furthermore, this new in vitro assay was used to re-test the response of several Class IIIb cyclase homology domains to inorganic carbon. Results demonstrated that mammalian soluble adenylyl cyclase was responsive to inorganic carbon, however, results provided evidence to suggest that two prokaryotic Class IIIb cyclase homology domains (CyaB1 from Anabaena PCC 7120 and CyaC from Spirulina platensis) were possibly non-responsive to inorganic carbon
Open access self-archiving: An author study
No full textThis, our second author international, cross-disciplinary study on open access had 1296 respondents. Its focus was on self-archiving. Almost half (49%) of the respondent population have self-archived at least one article during the last three years. Use of institutional repositories for this purpose has doubled and usage has increased by almost 60% for subject-based repositories. Self-archiving activity is greatest amongst those who publish the largest number of papers. There is still a substantial proportion of authors unaware of the possibility of providing open access to their work by self-archiving. Of the authors who have not yet self-archived any articles, 71% remain unaware of the option. With 49% of the author population having self-archived in some way, this means that 36% of the total author population (71% of the remaining 51%), has not yet been appraised of this way of providing open access. Authors have frequently expressed reluctance to self-archive because of the perceived time required and possible technical difficulties in carrying out this activity, yet findings here show that only 20% of authors found some degree of difficulty with the first act of depositing an article in a repository, and that this dropped to 9% for subsequent deposits. Another author worry is about infringing agreed copyright agreements with publishers, yet only 10% of authors currently know of the SHERPA/RoMEO list of publisher permissions policies with respect to self-archiving, where clear guidance as to what a publisher permits is provided. Where it is not known if permission is required, however, authors are not seeking it and are self-archiving without it. Communicating their results to peers remains the primary reason for scholars publishing their work; in other words,
researchers publish to have an impact on their field. The vast majority of authors (81%) would willingly comply with a mandate from their employer or research funder to deposit copies of their articles in an institutional or subject-based repository. A further 13% would comply reluctantly; 5% would not comply with such a mandate
Improvements in virological control among women conceiving on combination antiretroviral therapy in Western Europe.
No full textProgress of international hydrogen production network for the thermochemical Cu–Cl cycle
No full textThis paper presents recent advances by an international team which is developing the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production. Development of the Cu–Cl cycle has been pursued by several countries within the framework of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Due to its lower temperature requirements in comparison with other thermochemical cycles, the Cu–Cl cycle is particularly well matched with Canada's Generation IV reactor, SCWR (Super-Critical Water Reactor), as well as other heat sources such as solar energy or industrial waste heat. In this paper, recent developments of the Cu–Cl cycle are presented, specifically involving unit operation experiments, corrosion resistant materials and system integration.Atomic Energy of Canada LimitedOntario Research Excellence FundNatural Sciences and Engineering Research Council of CanadaUniversity Network of Excellence in Nuclear Engineering (UNENE)Canada Research Chairs progra
ŻYCIE UKRYTE W SŁOWIE. "BEKSIŃSCY. PORTRET PODWÓJNY" MAGDALENY GRZEBIAŁKOWSKIEJ W ŚWIETLE POSTSTRUKTURALIZMU
No full textLife Hidden in Words. Magdalena Grzebiałkowska\u27s "Beksińscy. Portret podwójny" and Poststructuralism
The article analyzes Magdalena Grzebiałkowska\u27s biographical "Beksińscy. Portret podwójny" which focuses on the lives of Zdzisław Beksiński and Tomasz Beksiński. The author looks at the construction of the biography and its relationship to poststructuralism, which allows for an appreciation of the literary features of the book. He points to how the specificity of the content, language, a mode of narration in Grzebiałkowska\u27s book make it a full-fledged literary work itself. As such the book departs from a typical biographical scheme. Juxtaposing the book with poststructural ideas leads to the reconsideration of the role of the author in the process of shaping of a biographical narrative
Systems, methods and devices for the capture and hydrogenation of carbon dioxide with thermochemical Cu—Cl and Mg—Cl—Na/K—CO2 cycles
No full textSystems, methods, and devices for producing hydrogen and capturing CO2 from emissions combine both H2 production and CO2 capture processes in forms of thermochemical cycles to produce useful products from captured CO2. The thermochemical cycles are copper-chlorine (Cu—Cl) and magnesium-chlorine-sodium/potassium cycles (Mg—Cl—Na/K—CO2). One system comprises a Cu—Cl cycle, a CO2 capture loop, and a hydrogenation cycle. Another system comprises an Mg—Cl—Na/K—CO2 cycle and a hydrogenation cycle. Devices for hydrogen production, CO2 capture, hydrogenation, and process and equipment integration include a two-stage fluidized/packed bed, hybrid two-stage spray-fluidized/packed bed reactor, a two-stage wet-mode absorber, a hybrid two-stage absorber, and a catalyst packed/fluidized bed reactor
Clean hydrogen production with the Cu–Cl cycle – Progress of international consortium, I: Experimental unit operations
No full textAdvancement of the thermochemical copper–chlorine (Cu–Cl) cycle for hydrogen production is reviewed and discussed in this paper. Individual unit operations and their linkage into an integrated cycle are being developed by a Canadian consortium, as part of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. This paper focuses on the consortium’s latest advances on the Cu–Cl cycle, particularly with respect to hydrogen production with Canada’s Generation IV reactor, called SCWR (Super-Critical Water Reactor). Other heat sources may also be utilized for the Cu–Cl cycle, such as solar energy or industrial waste heat. In this first of two companion papers, recent developments in Canada’s nuclear hydrogen program are reported, specifically unit operation experiments of the Cu–Cl cycle and system integration. The following second companion paper will present system modeling with Aspen Plus, corrosion resistant materials, thermochemistry, safety, and reliability aspects of the Cu–Cl cycle.Atomic Energy of Canada LimitedOntario Research Excellence FundNatural Sciences and Engineering Research Council of CanadaUniversity Network of Excellence in Nuclear Engineering (UNENE)Canada Research Chairs progra
Canada’s program on nuclear hydrogen production and the thermochemical Cu–Cl cycle
No full textThis paper presents an overview of the status of Canada’s program on nuclear hydrogen production and the thermochemical copper–chlorine (Cu–Cl) cycle. Enabling technologies for the Cu–Cl cycle are being developed by a Canadian consortium, as part of the Generation IV International Forum (GIF) for hydrogen production with the next generation of nuclear reactors. Particular emphasis in this paper is given to hydrogen production with Canada’s Super-Critical Water Reactor, SCWR. Recent advances towards an integrated lab-scale Cu–Cl cycle are discussed, including experimentation, modeling, simulation, advanced materials, thermochemistry, safety, reliability and economics. In addition, electrolysis during off-peak hours, and the processes of integrating hydrogen plants with Canada’s nuclear plants are presented.Atomic Energy of Canada LimitedOntario Research Excellence FundArgonne National Laboratory (International Nuclear Energy Research Initiative; U.S. Department of Energy)Natural Sciences and Engineering Research Council of Canada (NSERC)University Network of Excellence in Nuclear Engineering (UNENE)Canada Research Chairs (CRC
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