324 research outputs found
Dynamic network rating for low carbon distribution network operation - A U.K. application
© 2010-2012 IEEE. Dynamic asset rating (DAR) is one of the number of techniques that could be used to facilitate low carbon electricity network operation. Previous work has looked at this technique from an asset perspective. This paper focuses, instead, from a network perspective by proposing a dynamic network rating (DNR) approach. The models available for use with DAR are discussed and compared using measured load and weather data from a trial network area within Milton Keynes in the central area of the U.K. This paper then uses the most appropriate model to investigate, through a network case study, the potential gains in dynamic rating compared to static rating for the different network assets - transformers, overhead lines, and cables. This will inform the network operator of the potential DNR gains on an 11-kV network with all assets present and highlight the limiting assets within each season
Mono- and dinuclear N-heterocyclic carbene palladium complexes with diazine ligands and their catalytic activities toward the Mizoroki–Heck reaction
<p>Mono- and dinuclear N-heterocyclic carbene palladium complexes with diazine ligands were synthesized and characterized through adjusting the stoichiometric ratio of the reactants. The catalytic properties of all complexes were further studied in the Mizoroki–Heck reaction. The results indicated that the dinuclear complexes induced some benefits in catalytic behavior.</p
Synthesis and characterization of N-heterocyclic carbene–PdCl<sub>2</sub>–1<i>H</i>-benzotriazole complexes and their catalytic activities toward Mizoroki–Heck and Sonogashira reactions
<p>Four heteroleptic palladium complexes containing both N-heterocyclic carbenes and 1<i>H</i>-benzotriazole were synthesized and characterized. The solid-state structures show mononuclear carbene palladium complexes with each palladium coordinated by an NHC, the 3-position nitrogen of 1<i>H</i>-benzotriazole and two <i>trans</i> chlorides. The catalytic performance of the complexes for Mizoroki–Heck and Sonogashira reactions were further investigated. The results reveal that the complexes show high catalytic activities for coupling of aryl bromides with alkenes and alkynes.</p
Construction of polymeric Cu(I) <i>N</i>-heterocyclic carbene complex utilizing terpyridine-Fe(II) as linkers: formation of an efficient and recyclable catalyst
<p>A metal-coordination-driven self-assembly using the predesigned building block has been developed. Herein, the catalytic active NHC–Cu(I) units were introduced into the terpyridine metal coordination polymers. The self-assembled architecture, as a heterogeneous catalyst, was successfully used to catalyze the A<sup>3</sup>-coupling reaction of aldehyde, alkyne, and amine and Huisgen 1,3-dipolar cycloaddition reaction of azide and alkyne in high yields.</p
A Semi-Physiologically Based Pharmacokinetic Pharmacodynamic Model for Glycyrrhizin-Induced Pseudoaldosteronism and Prediction of the Dose Limit Causing Hypokalemia in a Virtual Elderly Population
<div><p>Glycyrrhizin (GL) is a widely used food additive which can cause severe pseudoaldosteronism at high doses or after a long period of consumption. The aim of the present study was to develop a physiologically based pharmacokinetic (PBPK) pharmacodynamic (PD) model for GL-induced pseudoaldosteronism to improve the safe use of GL. Since the major metabolite of GL, glycyrrhetic acid (GA), is largely responsible for pseudoaldosteronism via inhibition of the kidney enzyme 11β-hydroxysteroiddehydrogenase 2 (11β-HSD 2), a semi-PBPK model was first developed in rat to predict the systemic pharmacokinetics of and the kidney exposure to GA. A human PBPK model was then developed using parameters either from the rat model or from in vitro studies in combination with essential scaling factors. Kidney exposure to GA was further linked to an I<sub>max</sub> model in the 11β-HSD 2 module of the PD model to predict the urinary excretion of cortisol and cortisone. Subsequently, activation of the mineralocorticoid receptor in the renin-angiotensin-aldosterone-electrolyte system was associated with an increased cortisol level. Experimental data for various scenarios were used to optimize and validate the model which was finally able to predict the plasma levels of angiotensin II, aldosterone, potassium and sodium. The Monte Carlo method was applied to predict the probability distribution of the individual dose limits of GL causing pseudoaldosteronism in the elderly according to the distribution of sensitivity factors using serum potassium as an indicator. The critical value of the dose limit was found to be 101 mg with a probability of 3.07%.</p></div
Logit model results on farmers’ decisions to outsource agricultural production tasks.
<p>Logit model results on farmers’ decisions to outsource agricultural production tasks.</p
Use of agricultural outsourcing services by land size and labor endowment (%).
<p>Use of agricultural outsourcing services by land size and labor endowment (%).</p
ProPhos: A Ligand for Promoting Nickel-Catalyzed Suzuki-Miyaura Coupling Inspired by Mechanistic Insights into Transmetalation
Nickel-catalyzed Suzuki–Miyaura coupling (Ni-SMC)
offers
the potential to reduce the cost of pharmaceutical process synthesis.
However, its application has been restricted by challenges such as
slow reaction rates, high catalyst loading, and a limited scope of
heterocycles. Despite recent investigations, the mechanism of transmetalation
in Ni-SMC, often viewed as the turnover-limiting step, remains insufficiently
understood. We elucidate the “Ni-oxo” transmetalation
pathway, applying PPh2Me as the ligand, and identify the
formation of a nickel-oxo intermediate as the turnover-limiting step.
Building on this insight, we develop a scaffolding ligand, ProPhos,
featuring a pendant hydroxyl group connected to the phosphine via
a linker. The design preorganizes both the nucleophile and the nickel
catalyst, thereby facilitating transmetalation. This catalyst exhibits
fast kinetics and robust activity across a wide range of heteroarenes,
with a catalyst loading of 0.5–3 mol %. For arene substrates,
the catalyst loading can be further reduced to 0.1 mol %
Distribution of CL<sub>up</sub>, K<sub>co</sub>, and k<sub>ox,0</sub> related physiological factors in simulation of the individual dose limit for 1000 subjects by the Monte Carlo method.
a<p>The boundary is according to the extreme value for 21 samples.</p><p>Distribution of CL<sub>up</sub>, K<sub>co</sub>, and k<sub>ox,0</sub> related physiological factors in simulation of the individual dose limit for 1000 subjects by the Monte Carlo method.</p
Abbreviations of parameters of the physiologically based pharmacokinetic model for GL, GA and GAM.
<p>Abbreviations of parameters of the physiologically based pharmacokinetic model for GL, GA and GAM.</p
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