Propensity For Interactions Research Articles

The intracellular domains of the EphB6 and EphA10 receptor tyrosine pseudokinases function as dynamic signalling hubs.

EphB6 and EphA10 are two poorly characterised pseudokinase members of the Eph receptor family, which collectively serves as mediators of contact-dependent cell–cell communication to transmit extracellular cues into intracellular signals. As per their active counterparts, EphB6 and EphA10 deregulation is strongly linked to proliferative diseases. However, unlike active Eph receptors, whose catalytic activities are thought to initiate an intracellular signalling cascade, EphB6 and EphA10 are classified as catalytically dead, raising the question of how non-catalytic functions contribute to Eph receptor signalling homeostasis. In this study, we have characterised the biochemical properties and topology of the EphB6 and EphA10 intracellular regions comprising the juxtamembrane (JM) region, pseudokinase and SAM domains. Using small-angle X-ray scattering and cross-linking-mass spectrometry, we observed high flexibility within their intracellular regions in solution and a propensity for interaction between the component domains. We identified tyrosine residues in the JM region of EphB6 as EphB4 substrates, which can bind the SH2 domains of signalling effectors, including Abl, Src and Vav3, consistent with cellular roles in recruiting these proteins for downstream signalling. Furthermore, our finding that EphB6 and EphA10 can bind ATP and ATP-competitive small molecules raises the prospect that these pseudokinase domains could be pharmacologically targeted to counter oncogenic signalling.

Neuropharmacology of Antiseizure Drugs.

BackgroundAntiseizure drugs (ASDs) are the primary therapy for epilepsy, with more than 20 drugs introduced into clinical practice to date. These drugs are typically grouped by their mechanisms of action and therapeutic spectrum. This article aims to educate non‐neurologists and medical students about the new frontiers in the pharmacology of ASDs and presents the current state of the literature on the efficacy and tolerability of these agents.MethodsRandomized controlled trials, observational studies, and evidence‐based meta‐analyses of ASD efficacy and tolerability as initial monotherapy for epileptic seizures and syndromes were identified in PubMed, EMBASE, the Cochrane Library, and Elsevier Clinical Pharmacology.ResultsThe choice of ASD varies primarily according to the seizure type. Practical guidelines for ASD selection in patients with new‐onset and drug‐resistant epilepsy were recently published. The guidelines have shown that the newer‐generation drugs, which have unique mechanistic and pharmacokinetic properties, are better tolerated but have similar efficacy compared with the older drugs. Several ASDs are effective as first‐line monotherapy in focal seizures, including lamotrigine, carbamazepine, phenytoin, levetiracetam, and zonisamide. Valproate remains the first‐line drug for many patients with generalized and unclassified epilepsies. However, valproate should be avoided, if possible, in women of childbearing potential because of teratogenicity. Toxicity profile precludes several drugs from use as first‐line treatment, for example, vigabatrin, felbamate, and rufinamide.ConclusionsAntiseizure drugs have different pharmacologic profiles that should be considered when selecting and prescribing these agents for epilepsy. These include pharmacokinetic properties, propensity for drug‐drug interactions, and adverse effects.

Small Residues Inhibit Homo-Dimerization of the Human Carbonic Anhydrase XII Transmembrane Domain.

Amino acids with small side chains and motifs of small residues in a distance of four are rather abundant in human single-span transmembrane helices. While interaction of such helices appears to be common, the role of the small residues in mediating and/or stabilizing transmembrane helix oligomers remains mostly elusive. Yet, the mere existence of (small)xxx(small) motifs in transmembrane helices is frequently used to model dimeric TM helix structures. The single transmembrane helix of the human carbonic anhydrases XII contains a large number of amino acids with small side chains, and critical involvement of these small amino acids in dimerization of the transmembrane domain has been suggested. Using the GALLEX assay, we show here that the transmembrane domain indeed forms a strong transmembrane helix oligomer within a biological membrane. However, single or multiple mutations of small residue(s) to isoleucine almost always increased, rather than decreased, the interaction propensities. Reduction of helix flexibility and of protein–lipid contacts caused by a reduced lipid accessible surface area likely results in stabilization of helix–helix interactions within the membrane.

CatRAPID omics v2.0: going deeper and wider in the prediction of protein-RNA interactions.

Prediction of protein–RNA interactions is important to understand post-transcriptional events taking place in the cell. Here we introduce catRAPID omics v2.0, an update of our web server dedicated to the computation of protein–RNA interaction propensities at the transcriptome- and RNA-binding proteome-level in 8 model organisms. The server accepts multiple input protein or RNA sequences and computes their catRAPID interaction scores on updated precompiled libraries. Additionally, it is now possible to predict the interactions between a custom protein set and a custom RNA set. Considerable effort has been put into the generation of a new database of RNA-binding motifs that are searched within the predicted RNA targets of proteins. In this update, the sequence fragmentation scheme of the catRAPID fragment module has been included, which allows the server to handle long linear RNAs and to analyse circular RNAs. For the top-scoring protein–RNA pairs, the web server shows the predicted binding sites in both protein and RNA sequences and reports whether the predicted interactions are conserved in orthologous protein–RNA pairs. The catRAPID omics v2.0 web server is a powerful tool for the characterization and classification of RNA-protein interactions and is freely available at http://service.tartaglialab.com/page/catrapid_omics2_group along with documentation and tutorial.

Crystal and solution structures reveal oligomerization of individual capsid homology domains of Drosophila Arc.

Synaptic plasticity is vital for brain function and memory formation. One of the key proteins in long-term synaptic plasticity and memory is the activity-regulated cytoskeleton-associated protein (Arc). Mammalian Arc forms virus-like capsid structures in a process requiring the N-terminal domain and contains two C-terminal lobes that are structural homologues to retroviral capsids. Drosophila has two isoforms of Arc, dArc1 and dArc2, with low sequence similarity to mammalian Arc, but lacking a large N-terminal domain. Both dArc isoforms are related to the Ty3/gypsy retrotransposon capsid, consisting of N- and C-terminal lobes. Structures of dArc1, as well as capsids formed by both dArc isoforms, have been recently determined. We carried out structural characterization of the four individual dArc lobe domains. As opposed to the corresponding mammalian Arc lobe domains, which are monomeric, the dArc lobes were all oligomeric in solution, indicating a strong propensity for homophilic interactions. A truncated N-lobe from dArc2 formed a domain-swapped dimer in the crystal structure, resulting in a novel dimer interaction that could be relevant for capsid assembly or other dArc functions. This domain-swapped structure resembles the dimeric protein C of flavivirus capsids, as well as the structure of histones dimers, domain-swapped transcription factors, and membrane-interacting BAK domains. The strong oligomerization properties of the isolated dArc lobe domains explain the ability of dArc to form capsids in the absence of any large N-terminal domain, in contrast to the mammalian protein.

Exploring COBRAs, its antecedents and consequences in the context of banking brands

PurposeBrands have started investing heavily in their social media pages. Especially for banks having credence nature, the importance of engaging customers with the brand-related content on their social media pages has become a challenge. The present study explores the role of various characteristics of a brand's social media marketing efforts (SMME) and individual customer's general online social interaction propensity (GOSIP) on the customers' engagement/online brand-related activities (COBRAs). The subsequent effect of COBRAs on key banking outcomes such as satisfaction, trust and loyalty has also been evaluated. The moderating role of the customer–brand relationship length has also been evaluated.Design/methodology/approachA two-stage mixed-method approach was used for the data collection. Two focus group discussions were conducted for the preliminary stage, which resulted in identifying five Indian banking brands as stimuli for further study. For the main study, an online survey link was shared with the members of the stimuli banking brands' social media pages. A total of 552 useable responses were collected. After performing the exploratory factor analysis and common method bias tests, the collected data were analyzed using structural equation modeling and multi-group analysis.FindingsThe results of the present study have added all five characteristics (namely, entertainment, interaction, trendiness, customization and electronic word of mouth) of SMME and GOSIP as the key antecedents of the customers' engagement with brand content on social media pages or COBRAs. COBRAs have been found influencing the customers' satisfaction, but evidence of influence on the trust and loyalty has not been found. The length of the relationship between customers and the banking brand has been observed as an important moderator for the satisfaction–trust–loyalty relationship.Originality/valueThe present study has three unique contributions to the literature. Firstly, the study evaluates the role of customer-brand engagement on the banking brand's favorable outcomes such as satisfaction, trust and loyalty. Secondly, the exploration of the role of various social media marketing activities that can enhance customer–brand engagement. And finally, the study tests the moderating role of the customer–brand length of the relationship on the complete set of marketing activities–engagement–loyalty relationships.

Customer pre-participatory social media drivers and their influence on attitudinal loyalty within the retail banking industry: A multi-group analysis utilizing social exchange theory

Social media pervades everyday life and firms need to understand what consumer traits antedate participation over these channels. Utilizing social exchange theory (SET), this study seeks to determine what factors precede SET's cost-benefit analysis of social media participation along with these factors' influence on attitudinal loyalty. Important antecedents to this cost-benefit analysis for social media participation are online interaction propensity (OIP), participation attitude and trust. Further, demographic (age, gender, income) and social media page factors (perceived page size and page visit frequency) are identified as potential precursors to customers' cost-benefit analysis towards social media participation. A sample of 482 U.S. banking customers was collected via an online survey. The results found that OIP and trust had direct statistically significant effects on attitudinal loyalty and participation attitude's effect was fully mediated by trust. Age, gender and page visit frequency facets exhibited no differences between groups whilst income (with higher income groups displaying higher levels of loyalty) and page size groups (smaller page sizes demonstrated greater loyalty) demonstrated differing effects on attitudinal loyalty. The study contributes to knowledge and practice by extending particular pre-SET traits in social media to a U.S. retail banking context. The study also furthers academic and managerial capabilities for segmentation analysis' and explicating connections between pre-participatory influences and attitudinal loyalty.

Online biophysical predictions for SARS-CoV-2 proteins

BackgroundThe SARS-CoV-2 virus, the causative agent of COVID-19, consists of an assembly of proteins that determine its infectious and immunological behavior, as well as its response to therapeutics. Major structural biology efforts on these proteins have already provided essential insights into the mode of action of the virus, as well as avenues for structure-based drug design. However, not all of the SARS-CoV-2 proteins, or regions thereof, have a well-defined three-dimensional structure, and as such might exhibit ambiguous, dynamic behaviour that is not evident from static structure representations, nor from molecular dynamics simulations using these structures.MainWe present a website (https://bio2byte.be/sars2/) that provides protein sequence-based predictions of the backbone and side-chain dynamics and conformational propensities of these proteins, as well as derived early folding, disorder, β-sheet aggregation, protein-protein interaction and epitope propensities. These predictions attempt to capture the inherent biophysical propensities encoded in the sequence, rather than context-dependent behaviour such as the final folded state. In addition, we provide the biophysical variation that is observed in homologous proteins, which gives an indication of the limits of their functionally relevant biophysical behaviour.ConclusionThe https://bio2byte.be/sars2/ website provides a range of protein sequence-based predictions for 27 SARS-CoV-2 proteins, enabling researchers to form hypotheses about their possible functional modes of action.

Synergistic strengthening mechanisms of rhenium in nickel-based single crystal superalloys

A loading-unloading-reloading strategy via atomistic simulations is proposed to reveal the strengthening mechanisms of rhenium in nickel-based superalloys at ambient temperature. Simulations reproduce the experimentally observed increased flow stress with addition of rhenium. Besides the usual solid solution strengthening, two novel mechanisms are uncovered. One is that rhenium facilitates the dislocation nucleation and, thus, increases the propensity of forest dislocation interactions. The other involves a critical role of rhenium in promoting accumulation of sessile stair-rod dislocations, served as obstacles for the glissile dislocations. The three mechanisms synergistically render a stronger alloy, which is heuristic to design advanced superalloys in extreme environments.

Mechanistic Insights into the Co-Aggregation of Aβ and hIAPP: An All-Atom Molecular Dynamic Study.

Patients with Alzheimer's disease (AD) have a high risk of developing Type II diabetes (T2D). The co-aggregation of the two disease-related proteins, Aβ and hIAPP, has been proposed as a potential molecular mechanism. However, the detailed Aβ-hIAPP interactions and structural characteristics of co-aggregates are mostly unknown at atomic level. Here, we explore the conformational ensembles of the Aβ-hIAPP heterodimer and Aβ or hIAPP homodimer by performing all-atom explicit-solvent replica exchange molecular dynamic simulations. Our simulations show that the interaction propensity of Aβ-hIAPP in the heterodimer is comparable with that of Aβ-Aβ/hIAPP-hIAPP in the homodimer. Similar hot spot residues of Aβ/hIAPP in the homodimer and heterodimer are identified, indicating that both Aβ and hIAPP have similar molecular recognition sites for self-aggregation and co-aggregation. Aβ in the heterodimer possesses three high β-sheet probability regions: the N-terminal region E3-H6, the central hydrophobic core region K16-E22, and the C-terminal hydrophobic region I31-A41, which is highly similar to Aβ in the homodimer. More importantly, in the heterodimer, the regions E3-H6, F19-E22, and I31-M35 of Aβ and the amyloid core region N20-T30 of hIAPP display higher β-sheet probability than they do in homodimer, implying their crucial roles in the formation of β-sheet-rich co-aggregates. Our study sheds light on the co-aggregation of Aβ and hIAPP at an atomic level, which will be helpful for an in-depth understanding of the molecular mechanism for epidemiological correlation of AD and T2D.

Serum albumin: clinical significance of drug binding and development as drug delivery vehicle.

Human serum albumin, the primary transport and reservoir protein in the human circulatory system, interacts with numerous endogenous and exogenous ligands of varying structural characteristics. The mode of binding of drugs to albumin is central to understanding their pharmacokinetic profiles and has a major influence on their in vivo efficacy. Altered drug binding to albumin due to drug-drug interactions or abnormal physiology may result in marked changes in the active drug concentration, thus affecting its pharmacokinetic and pharmacodynamic properties. The propensity of drug-drug interaction to be clinically significant as well as possible exploitation of such interactions for therapeutic purposes is reviewed. Being the major organs of albumin metabolism, any impairment in the liver and kidney functions frequently alter the level of serum albumin, which affects the pharmacokinetic profiles of drugs and may have serious clinical implications. The natural function of serum albumin as a drug carrier is facilitated by its interaction with various cellular receptors. These receptors not only promote the uptake of drugs into cells but are also responsible for the extraordinarily long circulatory half-life of albumin. This property in combination with the presence of multiple ligand binding pockets have led to the emergence of serum albumin as an attractive vehicle for novel drug delivery systems. Here, we provide an overview of various albumin-based drug delivery strategies, classified according to their methods of drug attachment, and highlight their experimental and clinical successes.

Prediction of Transporter-Mediated Drug-Drug Interactions and Phenotyping of Hepatobiliary Transporters Involved in the Clearance of E7766, a Novel Macrocycle-Bridged Dinucleotide.

E7766 represents a novel class of macrocycle-bridged dinucleotides and is under clinical development for immuno-oncology. In this report, we identified mechanism of systemic clearance E7766 and investigated the hepatobiliary transporters involved in the disposition of E7766 and potential drug interactions of E7766 as a victim of organic anion-transporting polypeptide (OATP) inhibitors. In bile-duct cannulated rats and dogs, E7766 was mainly excreted unchanged in bile (>80%) and to a lesser extent in urine (<20%). Sandwich-cultured human hepatocytes (SCHHs), transfected cells, and vesicles were used to phenotype the hepatobiliary transporters involved in the clearance of E7766. SCHH data showed temperature-dependent uptake of E7766 followed by active biliary secretion. In vitro transport assays using transfected cells and membrane vesicles confirmed that E7766 was a substrate of OATP1B1, OATP1B3, and multidrug resistance-associated protein 2. Phenotyping studies suggested predominant contribution of OATP1B3 over OATP1B1 in the hepatic uptake of E7766. Studies in OATP1B1/1B3 humanized mice showed that plasma exposure of E7766 increased 4.5-fold when coadministered with Rifampicin. Physiologically based pharmacokinetic models built upon two independent bottom-up approaches predicted elevation of E7766 plasma exposure when administered with Rifampicin, a clinical OATP inhibitor. In conclusion, we demonstrate that OATP-mediated hepatic uptake is the major contributor to the clearance of E7766, and inhibition of OATP1B may increase its systemic exposure. Predominant contribution of OATP1B3 in the hepatic uptake of E7766 was observed, suggesting polymorphisms in OATP1B1 would be unlikely to cause variability in the exposure of E7766. SIGNIFICANCE STATEMENT: Understanding the clearance mechanisms of new chemical entities is critical to predicting human pharmacokinetics and drug interactions. A physiologically based pharmacokinetic model that incorporated parameters from mechanistic in vitro and in vivo experiments was used to predict pharmacokinetics and drug interactions of E7766, a novel dinucleotide drug. The findings highlighted here may shed a light on the pharmacokinetic profile and transporter-mediated drug interaction propensity of other dinucleotide drugs.

Potent antiproliferative active agents: novel bis Schiff bases and bis spiro β-lactams bearing isatin tethered with butylene and phenylene as spacer and DNA/BSA binding behavior as well as studying molecular docking

A [2+2]-cycloaddition of bis-isatin Schiff bases 5a–b and 7 with activated aryloxyacetic acid derivatives 8a–d afforded bis-spiroisatino β-lactams with aliphatic and aromatic spacers. The structures of the synthesized 2-oxindoles and spirooxindoles were determined based on Fourier-transform infrared spectroscopy, proton-1 and carbon-13 nuclear magnetic resonance spectroscopies and CHN analysis. Our interest in these bis-Schiff bases and bis-spiroisatino β-lactams is for their potential anticancer capabilities. In vitro bioactivity testing against the cervical adenocarcinoma (HeLa) and breast cancer (MCF-7) cell lines as well as noncancerous NIH/3T3 fibroblast cell was investigated applying the MTT assay. Bis-isatin derivatives 5a, 5b, 9h, 10a, and 10b showed promising antiproliferative activity toward these two cancer cell lines. Two of the bis-isatin Schiff bases, 5a and 5b, displayed IC50 values less than that of the clinically-used anticancer agent cisplatin towards both the MCF-7 and HeLa cells, while several of the bis-isatin β-lactams showed similar bioactivity to that of cisplatin. All of the oxindoles and spirooxindoles displayed a selective anticancer effect except 10b. To study the possible mechanism for this bioactivity, DNA and BSA binding analyses were performed using fluorescence and UV–visible spectroscopic techniques. The isatin adducts displayed excellent interaction propensity to CT-DNA as well as BSA. Molecular docking investigation carried out on DNA and BSA with promising molecules to show the possible mechanism of cytotoxicity activities.

PeptiDesCalculator: Software for computation of peptide descriptors. Definition, implementation and case studies for 9 bioactivity endpoints

We present a novel Java-based program denominated PeptiDesCalculator for computing peptide descriptors. These descriptors include: redefinitions of known protein parameters to suite the peptide domain, generalization schemes for the global descriptions of peptide characteristics, as well as empirical descriptors based on experimental evidence on peptide stability and interaction propensity. The PeptiDesCalculator software provides a user-friendly Graphical User Interface (GUI) and is parallelized to maximize the use of computational resources available in current work stations. The PeptiDesCalculator indices are employed in modeling 8 peptide bioactivity endpoints demonstrating satisfactory behavior. Moreover, we compare the performance of a support vector machine (SVM) classifier built using 15 PeptiDesCalculator indices with that of a recently reported deep neural network (DNN) antimicrobial activity classifier, demonstrating comparable test set performance notwithstanding the remarkably lower degree of freedom for the former. This software will facilitate the development of in silico models for the prediction of peptide properties.

Experimental and computational interaction studies of terbium (III) and lanthanide (III) complexes containing 2,2′-bipyridine with bovine serum albumin and their in vitro anticancer and antimicrobial activities

To investigate the chemotherapeutic and pharmacokinetic aspects of two lanthanide complexes (Tb(III) and La(III) containing 2,2′-bipyridine ligand), in vitro binding studies were carried out with BSA by employing multiple biophysical methods and molecular modeling study. There are different techniques containing fluorescence, absorption spectroscopy and competitive experiments to determine the interaction mode between BSA and these complexes. These complexes efficiently quenched the BSA emission through a static procedure. The results showed that the terbium and lanthanum complexes exhibited a high propensity for BSA interaction via van der Waals force. Further, competitive examination and docking study showed that the interaction site of these complexes on BSA is site III. The results of docking calculations were in good agreement with experimental examinations. Also, the energy transfer from BSA to these complexes has happened with high possibility. Moreover, antimicrobial studies of different bacterial and fungi indicated its promising antibacterial activity. In vitro cytotoxicity of the Tb complex and La complex was carried out in MCF-7 and A-549 cell lines, which revealed significantly good activity. Communicated by Ramaswamy H. Sarma

Halide Perovskites – Optoelectronic and Structural Characterization Methods

Halide Perovskites – Optoelectronic and Structural Characterization Methods

Edoxaban and the Issue of Drug-Drug Interactions: From Pharmacology to Clinical Practice.

Edoxaban, a direct factor Xa inhibitor, is the latest of the non-vitamin K antagonist oral anticoagulants (NOACs). Despite being marketed later than other NOACs, its use is now spreading in current clinical practice, being indicated for both thromboprophylaxis in patients with non-valvular atrial fibrillation (NVAF) and for the treatment and prevention of venous thromboembolism (VTE). In patients with multiple conditions, the contemporary administration of several drugs can cause relevant drug-drug interactions (DDIs), which can affect drugs' pharmacokinetics and pharmacodynamics. Usually, all the NOACs are considered to have significantly fewer DDIs than vitamin K antagonists; notwithstanding, this is actually not true, all of them are affected by DDIs with drugs that can influence the activity (induction or inhibition) of P-glycoprotein (P-gp) and cytochrome P450 3A4, both responsible for the disposition and metabolism of NOACs to a different extent. In this review/expert opinion, we focused on an extensive report of edoxaban DDIs. All the relevant drugs categories have been examined to report on significant DDIs, discussing the impact on edoxaban pharmacokinetics and pharmacodynamics, and the evidence for dose adjustment. Our analysis found that, despite a restrained number of interactions, some strong inhibitors/inducers of P-gp and drug-metabolising enzymes can affect edoxaban concentration, just as it happens with other NOACs, implying the need for a dose adjustment. However, our analysis of edoxaban DDIs suggests that given the small propensity for interactions of this agent, its use represents an acceptable clinical decision. Still, DDIs can be significant in certain clinical situations and a careful evaluation is always needed when prescribing NOACs.

Graph Convolutional Autoencoder and Generative Adversarial Network-Based Method for Predicting Drug-Target Interactions.

The computational prediction of novel drug-target interactions (DTIs) may effectively speed up the process of drug repositioning and reduce its costs. Most previous methods integrated multiple kinds of connections about drugs and targets by constructing shallow prediction models. These methods failed to deeply learn the low-dimension feature vectors for drugs and targets and ignored the distribution of these feature vectors. We proposed a graph convolutional autoencoder and generative adversarial network (GAN)-based method, GANDTI, to predict DTIs. We constructed a drug-target heterogeneous network to integrate various connections related to drugs and targets, i.e., the similarities and interactions between drugs or between targets and the interactions between drugs and targets. A graph convolutional autoencoder was established to learn the network embeddings of the drug and target nodes in a low-dimensional feature space, and the autoencoder deeply integrated different kinds of connections within the network. A GAN was introduced to regularize the feature vectors of nodes into a Gaussian distribution. Severe class imbalance exists between known and unknown DTIs. Thus, we constructed a classifier based on an ensemble learning model, LightGBM, to estimate the interaction propensities of drugs and targets. This classifier completely exploited all unknown DTIs and counteracted the negative effect of class imbalance. The experimental results indicated that GANDTI outperforms several state-of-the-art methods for DTI prediction. Additionally, case studies of five drugs demonstrated the ability of GANDTI to discover the potential targets for drugs.

Improving 2D Hybrid Energy Storage Electrode Homogeneity Via Graphene Oxide/Active Nanomaterial Electrophoretic Co-Deposition

Lithium-ion battery (LIB) electrode performance is directly related to charge movement within the electrode material. Improving electrode kinetics involves lowering the internal resistance which may be achieved through 1) nanosizing the active material to decrease the lithium-ion diffusion path; 2) using highly conductive additives; and 3) homogeneous microstructuring to form an effective percolation network for electron and ion conductive pathways. Among these highly conductive additives is the 2D graphene, or reduced graphene oxide (rGO, so-called due to its synthetic pathway). Which, thanks to its few-layers of densely packed sp2 hybridized carbon atoms with delocalized electrons, has excellent mechanical properties and electronic conductivity. However, achieving the desired homogeneity between active and conductive components is a challenge for the conventional tape-casting technique – particularly when nanosized and/or 2D nanomaterials are involved. The nano and 2D nature of the materials will present rheological challenges during the casting of the electrode slurry and result in mesoscale aggregation which is a property that triggers, or further accelerates, battery degradation. Thus, the benefits of nanosizing and using graphene are lost.Electrophoretic deposition (EPD) is a novel electrocoating technique capable of assembling coatings from a stable suspension through the application of an electric field. It is well accepted that EPD has excellent self-assembling capabilities and herein lies its advantage to being used to fabricate composite lithium-ion electrodes. EPD provides a simplified coating technique with short process times. Moreover, the versatility of the suspension also allows EPD to be potentially environmentally friendly – a property not available to the tape casting technique due to its use of the highly toxic N-Methyl-2-pyrrolidone solvent. The challenge of electrophoretically depositing graphene is that a stable graphene suspension is difficult to form due its strong propensity for interaction between sheets. Thus, this problem may be sidestepped by using graphene oxide (GO) which is a functionalized graphene derivative. The functional groups located on the graphene surface provide electrostatic repulsion which prevents aggregation during dispersion and also allows the use of more polar solvents. With this in mind, our McGill HydroMET group has successfully used EPD to fabricate binder-free composite electrodes with rGO as conductive material and lithium titanate spinel (Li4Ti5O12, LTO) or titanium niobate (TiNb2O7, TNO) as the nanosized active material. This was accomplished through co-deposition of conductive and, in the case of LTO, active material precursor followed by high temperature annealing to induce transformation of GO to rGO (and transformation of LTO precursor to the final spinel LTO) (Uceda, M., Chiu, H.-C., Gauvin, R., Zaghib, K., Demopoulos, G. P. (in press) Electrophoretically co-deposited Li4Ti5O12/reduced graphene oxide nanolayered composites for high-performance battery application. Energy Storage Materials). Both types EPD systems are then compared to conventionally casted electrodes through electrochemical testing and physical characterization. In both cases, EPD is shown to provide superior homogeneity which results in improved electrode kinetics and battery performance.Acknowledgments: This research was supported by Hydro-Quebec/NSERC grants and the McGill Sustainability Systems Initiative (MSSI).

Investigation of rice-straw-ash fouling/slagging and countermeasures using supplementary additives and co-firing with Si–Al-rich coal in a pilot-scale grate-fired combustor

This study aimed to investigate the alkali-related problems arising from firing a Thai rice-straw/rice-husk mixture in a pilot-scale grate-fired combustor (150 kWth) and to evaluate different countermeasures in order to mitigate these problems, i.e., addition of kaolin, co-firing with anthracite, and the synergistic effect of combining these measures. Chemical fractionation analysis was used as a preliminary indication of the propensity for interaction between the ash-forming elements in order to predict the slagging and fouling tendencies of the fuels. The results agreed well with those of the combustion experiments and the morphological and microstructural analyses of the bottom-ash and deposit samples via SEM-EDX and elemental mapping. Firing pure biofuels was found not to provoke sintering/slagging but instead resulted in severe fouling. The high deposition flux and significant impediment to the heat transfer of the deposit probe were attributed to the accumulation of condensing gas KCl and the impact of Si-based particles on the probe, as well as the K2SO4 aerosols originating from gas-phase sulfation. All the countermeasures applied showed a promising ability to reduce the deposit formation and prevent the heat transfer from deteriorating, particularly with kaolin or anthracite, or both, at stoichiometric amounts. The success of these countermeasures can be credited to the incorporation of the K-containing species released from biomass into the kaolin and anthracite minerals (a byproduct from the crushing process), as well as to the formation of high-temperature-melting K–Al- silicates. Another topic of interest was the exploitation of anthracite for any option, which could completely extinguish Cl in the deposits and simultaneously generate K2SO4, which may help to reduce chlorine corrosion.