Unveiling the role of cobalt species in the Co/N-C catalysts-induced peroxymonosulfate activation process

2021 ◽  
pp. 127784
Author(s):  
Huiwang Dai ◽  
Wenjun Zhou ◽  
Wei Wang ◽  
Zhiqi Liu
Keyword(s):  
Activation Process ◽  
Cobalt Species

AN "ACTIVATION" PROCESS FOR ENTREPRENEURIAL ENGINEERING EDUCATION: THE MODEL AND APPLICATION

2011 ◽  
Vol 19 (02) ◽  
pp. 147-168 ◽  
Author(s):  
GIANLUCA ELIA ◽  
A. MARGHERITA ◽  
G. SECUNDO ◽  
K. MOUSTAGHFIR
Keyword(s):  
Engineering Education ◽  
Research Training ◽  
Economic Value ◽  
Activation Process ◽  
Technology Entrepreneurship ◽  
Hands On ◽  
Research Training Program ◽  
Develop Technology ◽  
Market Solutions

The pervasiveness of scientific developments has raised the role of entrepreneurship as a driver of socio-economic value. Higher education institutions are thus asked to create entrepreneurial mindset and competencies with the purpose to make students people able to proactively identify opportunities and transform them in market solutions. In particular, engineering education programs can be of relevance to develop technology entrepreneurship competencies through hands-on and experiential approaches. In such vein, this paper proposes a model of entrepreneurship education as an "activation" process which uses four critical levers with the purpose to infuse the essence of entrepreneurship in tomorrow's engineering professionals. The application of the model is exemplified through the analysis of a research training program grounded in the aerospace domain. The key features of the initiative are discussed in the perspective of exploring new models of entrepreneurial engineering education.

The Influence of the Proton Gradient on the Activation of Ferredoxin-NADP+-oxidoreductase by Light

1988 ◽  
Vol 43 (3-4) ◽  
pp. 207-212 ◽  
Author(s):  
Roland Pschorn ◽  
Wolfgang Rühle ◽  
Aloysius Wild
Keyword(s):  
Active Form ◽  
Cytochrome F ◽  
Proton Gradient ◽  
Activation Process ◽  
Dark Light ◽  
Induction Kinetics ◽  
Fluorescence Quench ◽  
Steady State Rate ◽  
State Rate

Ferredoxin-NADP+-oxidoreductase (FNR, EC 1.18.1.2) has been shown to be activated by light within a few seconds during dark-light transitions and inactivated in the dark. In previous papers this could be pointed out by the correlation of cytochrome f induction kinetics to the rate of NADP-photoreduction and the variable fluorescence. The present study deals with the role of the proton gradient during the activation process. The transition from an inactive to an active form is followed continuously in an in situ system. The steady-state rate of NADP-photoreduction is affected only by ionophores which inhibit a formation of the proton gradient, but not by inhibitors of the electric field. It correlates to the 9-aminoacridine fluorescence quench and the light scattering signals at 535 nm. The perception of the pH-gradient through the enzyme is still a matter of discussion.

scholarly journals Rapid Loss of Factor XII- and XI-Activity in Ellagic Acid Activated Normal Plasma: Role of Plasma Inhibitors and Implications for Automated Aptt-Recording

1977 ◽  
Author(s):  
J. H. Joist ◽  
J. F. Cowan ◽  
M. Khan
Keyword(s):  
Ellagic Acid ◽  
Clinical Laboratory ◽  
Coagulation Factors ◽  
Activation Process ◽  
Factor Xii ◽  
Naturally Occurring ◽  
Normal Plasma ◽  
Factor Xiia ◽  
Loss Of Contact

Rapid prolongation of the activated partial thromboplastin time (aPTT) of normal plasma upon incubation with ellagic acid containing aPTT reagents was observed. The aPTT prolongation was not due to time dependent changes in pH in the incubation mixtures or loss of activity of the labile coagulation factors VIII and V, but occurred as a result of rapid progressive inactivation of ellagic acid activated factors XII and XI. Prolongation of the aPTT and loss of contact factor activities was not observed in plasma incubated with particulate activator reagents. This finding seemed to indicate that adsorption of factors XII and XI to larger particles during the activation process may protect these factors from inactivation by naturally occurring plasma inhibitors. Evidence is presented which supports previous observations that Ci-inhibitor, α1-antitrypsin and antithrombin III (in the presence of heparin contribute to factor XIIa- and XIa-inactivation in ellagic acid activated plasma and that plasma albumin may compete with factor XII for ellagic acid binding. The findings indicate that ellagic acid containing aPTT reagents have unfavorable properties which seriously limit their usefulness in the clinical laboratory, particularly in respect to recording of the aPTT with certain fully automated clot timers.

Role of Primary Sensory Cortex in Generalized Electrocortical Activation

1957 ◽  
Vol 189 (1) ◽  
pp. 137-140
Author(s):  
Aaron J. Beller ◽  
Gidon F. Gestring ◽  
Dominick P. Purpura
Keyword(s):  
Sensory Stimulation ◽  
Sensory Cortex ◽  
Activation Process ◽  
Afferent Activity ◽  
Primary Sensory Cortex ◽  
Cortical Regions ◽  
Somatic Sensory Cortex ◽  
Bilateral Destruction

Experiments were performed on intact unanesthetized-succinylcholine paralyzed cats in order to compare the effects of ablations of primary cortical regions on the ability to evoke generalized activation to specific sensory stimulation with those obtained by Bremer on encéphale isolé preparations. Bilateral destruction of the auditory or somatic sensory cortex in intact preparations does not block generalized activation to auditory or sciatic stimulation. It is concluded that in the presence of spinal afferent activity as exists in the intact preparation corticifugal influences arising in either the auditory or somatic sensory cortex are not necessary for the activation process that follows auditory or sciatic stimulation.

scholarly journals The SAM domain of mouse SAMHD1 is critical for its activation and regulation

2017 ◽  
Author(s):  
Olga Buzovetsky ◽  
Chenxiang Tang ◽  
Kirsten Knecht ◽  
Jenna M. Antonucci ◽  
Li Wu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Bound States ◽  
Restriction Factor ◽  
Activation Process ◽  
Catalytic Core ◽  
Sam Domain ◽  
And Function ◽  
Hiv 1 ◽  
Viral Reverse Transcription

ABSTRACTHuman SAMHD1 (hSAMHD1) is a retroviral restriction factor that blocks HIV-1 infection by depleting the cellular nucleotides required for viral reverse transcription. SAMHD1 is allosterically activated by nucleotides that induce assembly of the active tetramer. Although the catalytic core of hSAMHD1 has been studied extensively, previous structures have not captured the regulatory SAM domain. In this study, we determined the first crystal structure of full-length SAMHD1 by capturing mouse SAMHD1 (mSAMHD1) structures in three different nucleotide bound states. Although mSAMHD1 and hSAMHD1 are highly similar in sequence and function, we found that mSAMHD1 possesses a more complex nucleotide-induced activation process, highlighting the regulatory role of the SAM domain. Our results provide new insights into the regulation of SAMHD1 activity, thereby will facilitate the improvement of HIV mouse models and the development of new therapies for certain cancers and autoimmune diseases.

scholarly journals Artichoke as a non-conventional precursor for activated carbon: Role of the activation process

2017 ◽  
Vol 11 (5) ◽  
pp. 677-688 ◽  
Author(s):  
Gamal M.S. ElShafei ◽  
Ibrahim M.A. ElSherbiny ◽  
Atef S. Darwish ◽  
Christine A. Philip
Keyword(s):  
Activated Carbon ◽  
Activation Process

scholarly journals Activation of human complement serine-proteinase C1r is down-regulated by a Ca2+-dependent intramolecular control that is released in the C1 complex through a signal transmitted by C1q

1994 ◽  
Vol 301 (2) ◽  
pp. 509-516 ◽  
Author(s):  
N M Thielens ◽  
C Illy ◽  
I M Bally ◽  
G J Arlaud
Keyword(s):  
Serine Proteinase ◽  
Intrinsic Property ◽  
Inhibitory Effect ◽  
Activation Process ◽  
Activation Kinetics ◽  
Activation Reaction ◽  
Comparable Effect ◽  
Partial Release ◽  
Intramolecular Mechanism

The activation of human C1, a Ca(2+)-dependent complex proteinase comprising a non-enzymic protein, C1q, and two serine proteinases, C1r and C1s, is based primarily on the intrinsic property of C1r to autoactivate. The aim of the present study was to investigate the mechanisms involved in the regulation of C1r autoactivation, with particular attention to the role of Ca2+ ions. Spontaneous activation of proenzyme C1r was observed upon incubation in the presence of EDTA, whereas Ca2+ ions reduced markedly the activation process. Several lines of evidence indicated that Ca2+ inhibited the intramolecular activation reaction but had little or no effect on the intermolecular activation reaction. C1q caused partial release of this inhibitory effect of Ca2+. Complete stabilization of C1r in its proenzyme form was obtained upon incorporation within the Ca(2+)-dependent C1s-C1r-C1r-C1s tetramer, and a comparable effect was observed when C1s was replaced by its Ca(2+)-binding alpha-fragment. Both tetramers, C1s-C1r-C1r-C1s and C1s alpha-C1r-C1r-C1s alpha, readily associated with C1q to form 16.0 S and 14.7 S complexes respectively in which C1r fully recovered its activation potential. Both complexes showed indistinguishable activation kinetics, indicating that the gamma B catalytic region of C1s plays no role in the mechanism that triggers C1r activation in C1. The collagen-like fragments of C1q retained the ability to bind to C1s-C1r-C1r-C1s, but, in contrast with intact C1q, failed to induce C1r activation in the resulting complex at temperatures above 25 degrees C. On the basis of these observations it is proposed that activation of the serine-proteinase domain of C1r is controlled by a Ca(2+)-dependent intramolecular mechanism involving the Ca(2+)-binding alpha-region, and that this control is released in C1 by a signal originating in C1q and transmitted through the C1q/C1r interface.

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