bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Keynote) Electrochemistry for Studying and Using Biological and Synthetic Catalysts of Hydrogen Oxidation and Production
Authors: Léger Christophe 
Published: February 2020

Direct electrochemistry has proved invaluable for studying natural and synthetic catalysts of redox reactions that are of interest in the context of solar fuels production, including H2 oxidation and production. With the catalyst either attached to the electrode or free to diffuse in solution, the current response to changing the electrochemical driving force, the so-called voltammetric signature, can be interpreted to learn about various aspects of the mechanism that are difficult to probe using more conventional methods: long-range electron transfer, diffusion along gas channels, redox-driven (in)activations, active site chemistry and photoreactivity under conditions of turnover. It can also be used to define the sequence of events in the catalytic cycle and to benchmark the performances of the catalyst in terms of rate, directionality and reversibility. This approach contrasts with and complements the usual strategy which aims at stabilizing species that are presumed to be catalytic intermediates, and determining their structure using spectroscopic or structural methods. Embedding the enzyme in a film of redox polymer provides further opportunities for stabilising the enzyme-electrode and tuning its apparent properties, particularly the resistance to oxygen, making it possible to achieve long-term aerobic hydrogen oxidation using enzymes that are notoriously oxygen sensitive. Exemples will be given that illustrate electrochemical studies and applications of hydrogenase enzymes and synthetic catalysts.
[1] M. Del Barrio, Melisa and M. Sensi and C. Orain and C. Baffert and S. Dementin and V. Fourmond and C. Leger, “Electrochemical investigations of hydrogenases and other enzymes that produce and use solar fuels” Acc. Chem. Res. 51 769 (2018)
[2] M Sensi, M del Barrio, C Baffert, V Fourmond, C Leger “New perspectives in hydrogenase direct electrochemistry”, Curr. Op. Electrochem 1:5 135 (2017)
[3] V Fourmond and C. Leger, “Modelling the voltammetry of adsorbed enzymes and molecular catalysts”, Curr. Op. Electrochem 1:1, 110 (2017)
[4] Vincent Fourmond, Eric S. Wiedner, Wendy J. Shaw and Christophe Léger, “On the design of molecular catalysts of reversible and bidirectional H2 oxidation/production”, submitted.
[5] Huaiguang Li, Darren Buesen, Christophe Léger, Vincent Fourmond and Nicolas Plumeré, in preparation.

Figure 1
Spectro-Electrochemical Investigation of the Effects of Flavin Electron Transporters in Artificial and Bacterial Biofilms
Authors: Kastania Eleni , Stürm Heinz , Özcan Özlem 
Published: February 2020

Bacterial biofilms have the capacity to develop and thrive in virtually all circumstances and surfaces, even in the most challenging environmental conditions. The pervasive and recalcitrant existence of biofilms renders them to be a significant safety risk and economical encumbrance in a wide array of industries and technologies, and therefore is a priority area of research.
It is essential to develop an improved understanding of the mechanisms implicated during biofilm formation, such as in the case of the diffusion of bacterial-secreted extracellular electron transporters, which are purported to play an important role during biocorrosion by exoelectrogenic bacteria. Hence, a fundamental understanding of electron transfer mechanisms between bacteria and extracellular electron acceptors will contribute insight to our understanding of charge transport and chemistry at the biofilm – external insoluble electron acceptor interface.
In the present work, Attenuated Total Reflection - Fourier transform-infrared (ATR-FTIR) spectroscopy has been coupled to electrochemical techniques for the nondestructive, in situ spectro-electrochemical monitoring of biofilms in real-time. Shewanella sp. have been selected for this investigation due to their adaptable exoelectrogenic respiratory capacities and their notable ability to reduce metals via several different mechanisms of extracellular electron transfer mechanisms, including self-secreted flavin shuttles. Gold-thin film model substrates have been used due to their inert nature and for their ability to permit precise manipulation of the substrate surface polarization. Additionally, hydrogels comprised of calcium cross-linked alginate have been used to mimic the architectural features of extracellular polymeric substances which are integral to a bacterial biofilm, to allow the study of electron-transporting flavin molecules in an artificial biofilm. The results will demonstrate patterns of diffusion, akin to how flavins would diffuse in a naturally occurring biofilm, and how polarization affects this process. Furthermore, insight will be gained on how the redox behavior of flavins can influence the development and evolution of a biofilm.
This interdisciplinary approach should shed light on bacterial electron transfer mechanisms which could contribute towards emerging technologies which seek to better understand such mechanisms for novel antifouling strategies, renewable energies, and bioremediation.
Bioelectrochemical Nitrogen Fixation (e-BNF) Towards the Electrosynthesis of Biomass
Authors: Schievano Andrea , Rago Laura , Goglio Andrea , Marzorati Stefania , Zecchin Sarah , Cristiani Pierangela , Cavalca Lucia 
Published: February 2020

The industrial synthesis (Haber-Bosch process) of mineral-N has been showing its dark side. Facing the enormous challenge of feeding humankind new technological solutions should enable sustainable nitrogen (N) fixation, to preserve soil fertility. We introduce a new type of microbial electrosynthesis, aimed at simultaneously fixing N2 and inorganic carbon. In this new perspective, the aim is enhancing biological nitrogen fixation by electrostimulation of complex microbial communities, to produce whole biomass, which can be used as soil fertilizer.
Two preliminary contributions in this field reported: a) a bioelectrochemical version of the Haber-bosh process, where methyl viologen shuttled electrons to purified nitrogenase enzymes (Milton et al., 2017) and b) the stimulation of N-fixation in a pure planktonic culture of X. autotrophicus by H2-evolution with a specific abiotic catalyst (Liu et al., 2017).
Here, a cathodic biofilm was enriched in electro-active autotrophic nitrogen fixers, starting from a mixed microbial culture. The cathode, a carbon-fibers conductor, was kept under constant polarization (-0.7 V vs SHE). Biomass (in the biofilm, as well as in the bulk liquid phase) was synthesized at significantly higher rates (up to 18-fold), as compared to controls kept at open circuit (OC). Along over 100 days, electron transfer had increased by 30-fold, as compared to abiotic conditions. Metagenomics evidenced Nif genes associated to autotrophs (both Archaea and Bacteria) only in polarized biofilms, while not in OC control. Genes copies encoding for a series of known proteins associated to extracellular electron transfer were double in polarized trials, as compared to controls.
The first results of such an approach were recently published in Bioelectrochemistry (Rago et al., 2019). From this proof-of-the-concept, we propose to call this promising field ‘bio-electrochemical nitrogen fixation (e-BNF)’, that deserve future research efforts in both fundamentals and applicative aspects.
Liu, C., Sakimoto, K.K., Colón, B.C., Silver, P.A., Nocera, D.G., 2017. Ambient nitrogen reduction cycle using a hybrid inorganic–biological system. Proc. Natl. Acad. Sci. 114, 6450–6455. doi:10.1073/pnas.1706371114
Milton, R.D., Cai, R., Abdellaoui, S., Leech, D., De Lacey, A.L., Pita, M., Minteer, S.D., 2017. Bioelectrochemical Haber–Bosch Process: An Ammonia-Producing H2/N2Fuel Cell. Angew. Chemie - Int. Ed. 56, 2680–2683. doi:10.1002/anie.201612500
Rago, L., Zecchin, S., Villa, F., Goglio, A., Corsini, A., Cavalca, L. & Schievano, A. 2019, ‘Bioelectrochemical Nitrogen fixation (e-BNF): Electro-stimulation of enriched biofilm communities drives autotrophic nitrogen and carbon fixation’, Bioelectrochemistry, vol. 125, pp. 105–15.

Figure 1
(Invited) Controlling the Selectivity and Catalytic Activity of Bio-Inspired Transition Metal Complexes for the Oxygen Reduction Reaction
Authors: Elbaz Lior 
Published: February 2020

In the search for abundant precious group metal free (PGM-free) catalysts, it was biological systems that inspired researchers over the years. One of the most prominent groups of such bio-inspired catalysts are transition metal/nitrogen/carbon-based catalysts (MNC), among them are heme-like molecular catalysts such as porphyrins and phthalocyanins.
Most of the bio-inspired catalysts designed to-date, focused solely on the catalytic center of molecular catalysts found in biological systems, while neglecting the electron mediators and ligands, which seem to have an important role in the catalytic scheme. It was shown that Imidazole for instance, is an important ligands which plays a vital role in biological systems, and can also be used to affect the catalytic activity of molecular catalysts. Some have used imidazoles and their analogues to study such effects, and showed significant control over the overpotential and selectivity upon the addition of such ligands to macrocyclic compounds. Another important molecule in enzymatic processes is quinone and its derivatives which also acts as an electron mediator in electron transport processes. It was shown recently that when incorporating certain axial ligand to the metal center in a metal-phthalocyanine, there is an increase in activity towards ORR, and that it induces a change in the mechanism of the reaction.
To enhance the ORR kinetics and selectivity by lowering the energy barriers, it is suggested herein to imbed ligands that have an imidazole group on reduced graphene oxide (rGO) and anchor porphyrins to them via coordinative bonds.
In this talk I will present a bio-mimetic catalytic structure as a new approach to increase the oxygen reduction catalytic selectivity of transition metal complexes. As in biological systems, where there is a series of mediators between the active site and the surface, that lowers the activation energy of the overall reaction and increases its selectivity, we used in this study a structure where a molecular catalyst Fe(III)tetrakis(1-methyl-4-pyridyl) porphyrin bonded to a surface via a benzimidazole mediator. Using electron paramagnetic resonance (EPR), UV-vis spectroscopy and electrochemical measurements, we compared the ORR activity of the molecular catalyst with and without benzimidazole and show that this ligand strongly influences the selectivity of the reaction and shifts it from the 2 to the 2+2-electron reduction.
(Invited) Single Nanoparticle Electrocatalysis – A Promising Approach To Measure the Catalytic Performance of Bio-Inspired Nanocatalysts
Authors: Tschulik Kristina 
Published: February 2020

The development of biomimetic and bio-inspired nanocatalysts is amongst to emerging topics in electrocatalysis, offering highly promising routes towards robust and highly active precious metal-free catalysts for a variety of economically relevant reactions.
Identification of the inherent activity of these nanomaterials is challenging, as typically additives and binders have to mixed with the active material to allow their electrochemical characterization. The individual contributions of the active catalyst material is difficult to dissect. The analysis of individual nanocatalyst particles, one at a time, is realized in the absence of additional components. It probes the electrocatalytic response of particles dispersed in the electrolyte solution during their sporadic collisions at an ultramicroelectrode [1,2]. This approach may guide the design of improved bio-inspired nanocatalysts based on the derived fundamental insights gained on a single particle level.
Herein, we demonstrate the application of nano impact electrochemistry as an additive-free method to study electrocatalysts at precious metal-free nanocatalysts for the oxygen evolution reaction.
References:
[1] Li, Xiuting; Batchelor-McAuley, Christopher; Whitby, Samuel A. I.; Tschulik, Kristina; Shao, Lidong; Compton, Richard G.

Angewandte Chemie (International ed. in English), 2016, 55(13), 4296–4299
[2] Stevenson, Keith J.; Tschulik, Kristina, Current Opinion in Electrochemistry, 2017, 6, 38–45.
Graphene Quantum Dots Embedded Multiwall Carbon Nanotube for the Electrochemical Detection of Dopamine in Human Serum Sample
Authors: Govindaraju Saravanan , Jang Chang Hyun , Yun Kyusik 
Published: February 2020

A highly sensitive and selective electrochemical sensor was developed by the graphene quantum dots embedded multiwall carbon nanotube (GQDS@MWCNT) for the detection of dopamine in the human serum sample. Glucose based graphene quantum dots were synthesized and embedded with the multiwall carbon nanotube by the physiochemical interaction. Synthesized GQDS@MWCNT were characterized with UV-vis spectroscopy, Raman spectroscopy and High-resolution transmission. Graphene quantum dots were 1-3 nm in size and spherical in shape. Graphene quantum dots were well embedded with multiwall carbon nanotube. Electroanalytical sensitivity and selectivity were determined with cyclic voltammetry and differential pulse voltammetry. The electrochemical performance of synthesized materials was analyzed with different pH from 2 to 10 and also performed with ferry cyanide. The linear range of dopamine detection was found to be 0.25 µM to 250 µM and the detection limit is 18 nM. In addition, high reproducibility, stability and selectivity were obtained in the experiment. Moreover, the fabricated GQDS@MWCNT sensor was successfully applied in the determination of dopamine concentrations in human serum samples with satisfactory recoveries. The developed sensor is suitable for the medical and pharmaceutical field.
Keywords: GQDS@MWCNT, Dopamine,Electrochemical Sensor, Human Serum Sample.

Figure 1
Exploiting Preexisting Immunity to Enhance Oncolytic Cancer Immunotherapy
Authors: Tähtinen Siri , Feola Sara , Capasso Cristian , Laustio Netta , Groeneveldt Christianne , Ylösmäki Erkko O. , Ylösmäki Leena , Martins Beatriz , Fusciello Manlio , Medeot Marta , Tagliamonte Maria , Chiaro Jacopo , Hamdan Firas , Peltonen Karita , Ranki Tuuli , Buonaguro Luigi , Cerullo Vincenzo 
Published: February 2020

AbstractBecause of the high coverage of international vaccination programs, most people worldwide have been vaccinated against common pathogens, leading to acquired pathogen-specific immunity with a robust memory T-cell repertoire. Although CD8+ antitumor cytotoxic T lymphocytes (CTL) are the preferred effectors of cancer immunotherapy, CD4+ T-cell help is also required for an optimal antitumor immune response to occur. Hence, we investigated whether the pathogen-related CD4+ T-cell memory populations could be reengaged to support the CTLs, converting a weak primary antitumor immune response into a stronger secondary one. To this end, we used our PeptiCRAd technology that consists of an oncolytic adenovirus coated with MHC-I–restricted tumor-specific peptides and developed it further by introducing pathogen-specific MHC-II–restricted peptides. Mice preimmunized with tetanus vaccine were challenged with B16.OVA tumors and treated with the newly developed hybrid TT-OVA-PeptiCRAd containing both tetanus toxoid- and tumor-specific peptides. Treatment with the hybrid PeptiCRAd significantly enhanced antitumor efficacy and induced TT-specific, CD40 ligand-expressing CD4+ T helper cells and maturation of antigen-presenting cells. Importantly, this approach could be extended to naturally occurring tumor peptides (both tumor-associated antigens and neoantigens), as well as to other pathogens beyond tetanus, highlighting the usefulness of this technique to take full advantage of CD4+ memory T-cell repertoires when designing immunotherapeutic treatment regimens. Finally, the antitumor effect was even more prominent when combined with the immune checkpoint inhibitor anti–PD-1, strengthening the rationale behind combination therapy with oncolytic viruses.Significance:These findings establish a novel technology that enhances oncolytic cancer immunotherapy by capitalizing on pre-acquired immunity to pathogens to convert a weak antitumor immune response into a much stronger one.
Lipid Trait Variants and the Risk of Non-Hodgkin Lymphoma Subtypes: A Mendelian Randomization Study
Authors: Kleinstern Geffen , Camp Nicola J. , Berndt Sonja I. , Birmann Brenda M. , Nieters Alexandra , Bracci Paige M. , McKay James D. , Ghesquières Hervé , Lan Qing , Hjalgrim Henrik , Benavente Yolanda , Monnereau Alain , Wang Sophia S. , Zhang Yawei , Purdue Mark P. , Zeleniuch-Jacquotte Anne , Giles Graham G. , Vermeulen Roel , Cocco Pierluigi , Albanes Demetrius , Teras Lauren R. , Brooks-Wilson Angela R. , Vajdic Claire M. , Kane Eleanor , Caporaso Neil E. , Smedby Karin E. , Salles Gilles , Vijai Joseph , Chanock Stephen J. , Skibola Christine F. , Rothman Nathaniel , Slager Susan L. , Cerhan James R. 
Published: February 2020

Abstract

Background:
Lipid traits have been inconsistently linked to risk of non-Hodgkin lymphoma (NHL). We examined the association of genetically predicted lipid traits with risk of diffuse large B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), and marginal zone lymphoma (MZL) using Mendelian randomization (MR) analysis.

Methods:
Genome-wide association study data from the InterLymph Consortium were available for 2,661 DLBCLs, 2,179 CLLs, 2,142 FLs, 824 MZLs, and 6,221 controls. SNPs associated (P &lt; 5 × 10−8) with high-density lipoprotein (HDL, n = 164), low-density lipoprotein (LDL, n = 137), total cholesterol (TC, n = 161), and triglycerides (TG, n = 123) were used as instrumental variables (IV), explaining 14.6%, 27.7%, 16.8%, and 12.8% of phenotypic variation, respectively. Associations between each lipid trait and NHL subtype were calculated using the MR inverse variance–weighted method, estimating odds ratios (OR) per standard deviation and 95% confidence intervals (CI).

Results:
HDL was positively associated with DLBCL (OR = 1.14; 95% CI, 1.00–1.30) and MZL (OR = 1.09; 95% CI, 1.01–1.18), while TG was inversely associated with MZL risk (OR = 0.90; 95% CI, 0.83–0.99), all at nominal significance (P &lt; 0.05). A positive trend was observed for HDL with FL risk (OR = 1.08; 95% CI, 0.99–1.19; P = 0.087). No associations were noteworthy after adjusting for multiple testing.

Conclusions:
We did not find evidence of a clear or strong association of these lipid traits with the most common NHL subtypes. While these IVs have been previously linked to other cancers, our findings do not support any causal associations with these NHL subtypes.

Impact:
Our results suggest that prior reported inverse associations of lipid traits are not likely to be causal and could represent reverse causality or confounding.
Myocardial Ischemia in Children With Anomalous Aortic Origin of a Coronary Artery With Intraseptal Course
Authors: Doan Tam T. , Zea-Vera Rodrigo , Agrawal Hitesh , Mery Carlos M. , Masand Prakash , Reaves-O’Neal Dana L. , Noel Cory V. , Qureshi Athar M. , Sexson-Tejtel S. Kristen , Fraser Charles D. , Molossi Silvana 
Published: February 2020

Background:
Intraseptal anomalous aortic origin of a coronary artery is considered a benign condition. However, there have been case reports of patients with myocardial ischemia, arrhythmia, and sudden cardiac death. The purpose of this study was to determine the clinical presentation, myocardial perfusion on provocative stress testing, and management of children with anomalous aortic origin of a coronary artery with an intraseptal course in a prospective cohort.

Methods:
Patients with anomalous aortic origin of a coronary artery and intraseptal course were prospectively enrolled from December 2012 to May 2019, evaluated, and managed following a standardized algorithm. Myocardial perfusion was assessed using stress imaging. Fractional flow reserve was performed in patients with myocardial hypoperfusion on noninvasive testing. Exercise restriction, β-blockers, and surgical intervention were discussed with the families.

Results:
Eighteen patients (female 6, 33.3%), who presented with no symptoms (10, 55.6%), nonexertional (4, 22.2%), and exertional symptoms (4, 22.2%), were enrolled at a median age of 12.4 years (0.3–15.9). Perfusion imaging was performed in 14/18 (77.8%) and was abnormal in 7/14 (50%); fractional flow reserve was positive in 5/8 (62.5%). All 4 patients with exertional symptoms and 3/10 (30%) with no or nonexertional symptoms had myocardial hypoperfusion. Coronary artery bypass grafting was performed in a 4-year-old patient; β-blocker and exercise restriction were recommended in 4 patients not suitable for surgery. One patient had nonexertional chest pain and 17 were symptom-free at median follow-up of 2.5 years (0.2–7.1).

Conclusions:
Up to 50% of patients with intraseptal anomalous aortic origin of a coronary artery had inducible myocardial hypoperfusion during noninvasive provocative testing. Long-term follow-up is necessary to understand the natural history of this rare anomaly.
Long‐Term Effects of Transcatheter Aortic Valve Implantation on Coronary Hemodynamics in Patients With Concomitant Coronary Artery Disease and Severe Aortic Stenosis
Authors: Vendrik Jeroen , Ahmad Yousif , Eftekhari Ashkan , Howard James P. , Wijntjens Gilbert W. M. , Stegehuis Valerie E. , Cook Christopher , Terkelsen Christian J. , Christiansen Evald H. , Koch Karel T. , Piek Jan J. , Sen Sayan , Baan Jan 
Published: February 2020

Background
As younger patients are being considered for transcatheter aortic valve implantation (TAVI), the assessment and treatment of concomitant coronary artery disease is taking on increased importance.

Methods and Results

Thirteen contemporary lower‐risk patients with TAVI with severe aortic stenosis (AS) and moderate‐severe coronary lesions were included. Patients underwent assessment of coronary hemodynamics in the presence of severe AS (pre‐
TAVI
), in the absence of severe AS (immediately post‐
TAVI
), and at longer‐term follow‐up (6 months post‐
TAVI
). Fractional flow reserve decreased from 0.85 (0.76–0.88) pre‐
TAVI
to 0.79 (0.74–0.83) post‐
TAVI
, and then to 0.71 (0.65–0.77) at 6‐month follow‐up (
P
<0.001 for all comparisons). Conversely, instantaneous wave‐free ratio was not significantly different: 0.82 (0.80–0.90) pre‐
TAVI
, 0.83 (0.77–0.88) post‐
TAVI
, and 0.83 (0.73–0.89) at 6 months (
P
=0.735). These changes are explained by the underlying coronary flow. Hyperemic whole‐cycle coronary flow (fractional flow reserve flow) increased from 26.36 cm/s (23.82–31.82 cm/s) pre‐
TAVI
to 30.78 cm/s (29.70–34.68 cm/s) post‐
TAVI
(
P
=0.012), to 40.20 cm/s (32.14–50.00 cm/s) at 6‐month follow‐up (
P
<0.001 for both comparisons). Resting flow during the wave‐free period of diastole was not significantly different: 25.48 cm/s (21.12–33.65 cm/s) pre‐
TAVI
, 24.54 cm/s (20.74–27.88 cm/s) post‐
TAVI
, and 25.89 cm/s (22.57–28.96 cm/s) at 6 months (
P
=0.500).

Conclusions

TAVI
acutely improves whole‐cycle hyperemic coronary flow, with ongoing sustained improvements at longer‐term follow‐up. This enhanced response to hyperemic stimuli appears to make fractional flow reserve assessment less suitable for patients with severe AS. Conversely, resting diastolic flow is not significantly influenced by the presence of severe AS. Resting indices of coronary stenosis severity, therefore, appear to be more appropriate for this patient population, although large‐scale prospective randomized trials will be required to determine the role of coronary physiology in patients with severe AS.