Potential-Modulated Ion Distributions in the Back-to-Back Electrical Double Layers at a Polarised Liquid|Liquid Interface Regulate the Kinetics of Interfacial Electron Transfer

Biphasic interfacial electron transfer (IET) reactions at polarisable liquid|liquid (L|L) interfaces underpin new approaches to electrosynthesis, redox electrocatalysis, bioelectrochemistry and artificial photosynthesis. Herein, using cyclic and alternating current voltammetry, we demonstrate that under certain experimental conditions, the biphasic 2-electron O2 reduction reaction can proceed by single-step IET between a reductant in the organic phase, decamethylferrocene, and interfacial protons in the presence of O2. Using this biphasic system, we demonstrate that the applied interfacial Galvani potential difference ΔwoØ provides no direct driving force to realise a thermodynamically uphill biphasic IET reaction in the mixed solvent region. We show that the onset potential for a biphasic single-step IET reaction does not correlate with the thermodynamically predicted standard Galvani IET potential and is instead closely correlated with the potential of zero charge at a polarised L|L interface. We outline that the applied ΔwoØ required to modulate the interfacial ion distributions, and thus kinetics of IET, must be optimised to ensure that the aqueous and organic redox species are present in substantial concentrations at the L|L interface simultaneously in order to react.M.D.S. acknowledges funding from Science Foundation Ireland (SFI) under grant no. 13/SIRG/2137 and the European Research Council through a Starting Grant (agreement no. 716792). A.G.-Q. acknowledges funding received from an Irish Research Council (IRC) Government of Ireland Postdoctoral Fellowship Award (grant number GOIPD/2018/252) and a Marie Skłodowska-Curie Postdoctoral Fellowship (Grant Number MSCA-IF-EF-ST 2020/101018277)

Understanding Digestive Ripening of Ligand-Stabilized, Charged Metal Nanoparticles

Most syntheses of thiolate-protected metal nanoparticles (NPs) include a thermochemical step in which the as-prepared, polydisperse NPs are transformed to a narrower size distribution in a poorly understood process known as digestive ripening (DR). Previous theoretical approaches considered either surface and electrostatic contributions or surface and ligand-binding contributions. We show that the three contributions are needed to obtain theoretical predictions in agreement with experimental observations. Although statistical thermodynamics does not clarify mechanistic details, it certainly provides valuable insights on the DR process. Remarkably, a relatively simple theory with no fitting parameters satisfactorily explains the roles of the metal:ligand ratio, the NP charge, the relative permittivity of the solvent, the ripening temperature, the binding energy, and the ligand chain length

Variation of the Fermi level and the Electrostatic Force of a Metallic Nanoparticle upon Colliding with an Electrode

When a metallic nanoparticle (NP) comes in close contact with an electrode, its Fermi level equilibrates with that of the electrode if their separation is less than the cut-off distance for electron tunnelling. In the absence of chemical reactions in solution, the charge on the metallic nanoparticle is constant outside this range before or after the collision. However, the double layer capacitances of both the electrode and the NP are influenced by each other, varying as the function of distance. Because the charge on the nanoparticle is constant, the outer potential of the metallic NP and hence its Fermi level varies as the capacitance changes. This effect is more pronounced for small particles (< 10 nm) in diluted supporting electrolyte solutions, especially if the metallic nanoparticle and the electrode have different potentials of zero charge. Nanoparticles were found to be more electrochemically active in the vicinity of the electrode. For example, the outer potential of a positively-polarized 2 nm radius NP was predicted to decrease by 35 mV or 100 mV (depending on the electrostatic model used to describe the electric double layer), when the NP moved from an electrode at 1 V (vs. its pzc) to the bulk. The force between the equilibrated NP and the electrode is always repulsive when they have the same pzc. Otherwise there can be an attraction even when the NP and the electrode carry charges of the same sign, due to the redistibution of surface charge density at both the NP and electrode surface

Synchronization of coupled single-electron circuits based on nanoparticles and tunneling junctions

We explore theoretically the synchronization properties of a device composed of coupled single-electron circuits whose building blocks are nanoparticles interconnected with tunneling junctions. Elementary nanoscillators can be achieved by a single-electron tunneling cell where the relaxation oscillation is induced by the tunneling. We develop a model to describe the synchronization of the nanoscillators and present sample calculations to demonstrate that the idea is feasible and could readily find applications. Instead of considering a particular system, we analyze the general properties of the device making use of an ideal model that emphasizes the essential characteristics of the concept. We define an order parameter for the system as a whole and demonstrate phase synchronization for sufficiently high values of the coupling [email protected] [email protected] [email protected]

Obesity-associated variants within FTO form long-range functional connections with IRX3

PMCID: PMC4113484.-- et al.Genome-wide association studies (GWAS) have reproducibly associated variants within introns of FTO with increased risk for obesity and type 2 diabetes (T2D). Although the molecular mechanisms linking these noncoding variants with obesity are not immediately obvious, subsequent studies in mice demonstrated that FTO expression levels influence body mass and composition phenotypes. However, no direct connection between the obesity-associated variants and FTO expression or function has been made. Here we show that the obesity-associated noncoding sequences within FTO are functionally connected, at megabase distances, with the homeobox gene IRX3. The obesity-associated FTO region directly interacts with the promoters of IRX3 as well as FTO in the human, mouse and zebrafish genomes. Furthermore, long-range enhancers within this region recapitulate aspects of IRX3 expression, suggesting that the obesity-associated interval belongs to the regulatory landscape of IRX3. Consistent with this, obesity-associated single nucleotide polymorphisms are associated with expression of IRX3, but not FTO, in human brains. A direct link between IRX3 expression and regulation of body mass and composition is demonstrated by a reduction in body weight of 25 to 30% in Irx3-deficient mice, primarily through the loss of fat mass and increase in basal metabolic rate with browning of white adipose tissue. Finally, hypothalamic expression of a dominant-negative form of Irx3 reproduces the metabolic phenotypes of Irx3-deficient mice. Our data suggest that IRX3 is a functional long-range target of obesity-associated variants within FTO and represents a novel determinant of body mass and composition.This work was funded by grants from the National Institutes of Health (DK093972, HL119967, HL114010 and DK020595) to M.A.N. and (MH101820, MH090937 and DK20595) to N.J.C. J.L.G.-S. was funded by grants from the Spanish Ministerio de Economía y Competitividad (BFU2010-14839, CSD2007-00008) and the Andalusian Government (CVI-3488). C.-C.H. was supported by a grant from the Canadian Institute of Health Research. K.-H.K. is supported by a fellowship from the Heart and Stroke Foundation of Canada. S.S. is supported by an NIH postdoctoral training grant (T32HL007381)Peer Reviewe

Anatomy of the ankle ligaments: a pictorial essay

Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail

Implantes estrechos como alternativa para la restauración del sector estético anterior

Existen determinadas situaciones donde los implantes, considerados estándar, no se pueden colocar o suponen un riesgo para el mantenimiento de la cresta marginal. Los implantes de diámetro estrecho se han empleado para numerosas indicaciones, estableciéndose protocolos de tratamiento, científicamente fundamentados, con excelentes resultados a largo plazo. En el presente trabajo presentamos una revisión histórica de los implantes estrechos, destacando sus indicaciones y limitaciones y presentamos un caso clínico en el que se han mostrado útiles. CASO CLÍNICO. Se presenta el caso de una mujer de 59 años de edad, con antecedentes de cáncer de mama en el 2008, que precisa la extracción de los cuatro incisivos supriores. El caso se resuelve con dos implantes estrechos postextracción y prótesis inmediata para preservar el aspecto estético. Conclusiones. En el caso que presentamos se evidencia que los implantes estrechos son una alternativa cuando rehabilitamos espacios edéntulos con poca disponibilidad ósea en el sentido horizontal o espacios mesio-distales reducidos en zonas estéticas

Tissue compatibility of SN-38-loaded anticancer nanofiber matrices

Delivery of chemotherapy in the surgical bed has shown preclinical activity to control cancer progression upon subtotal resection of pediatric solid tumors, but whether this new treatment is safe for tumor-adjacent healthy tissues remains unknown. Here, Wistar rats are used to study the anatomic and functional impact of electrospun nano¿ber matrices eluting SN-38—a potent chemotherapeutic agent—on several body sites where pediatric tumors such as neuroblastoma, Ewing sarcoma, and rhabdomyosarcoma arise. Blank and SN-38-loaded matrices embracing the femoral neurovascular bundle or in direct contact with abdominal viscera (liver, kidney, urinary bladder, intestine, and uterus) are placed. Foreign body tissue reaction to the implants is observed though no histologic damage in any tissue/organ. Skin healing is normal. Tissue reaction is similar for SN-38-loaded and blank matrices, with the exception of the hepatic capsule that is thicker for the former although within the limits consistent with mild foreign body reaction. Tissue and organ function is completely conserved after local treatments, as assessed by the rotarod test (forelimb function), hematologic tests (liver and renal function), and control of clinical signs. Overall, these ¿ndings support the clinical translation of SN-38-loaded nano¿ber matrices to improve local control strategies of surgically resected tumorsPostprint (author's final draft