Harnessing Effective Molarity to Design an Electrochemical DNA‐based Platform for Clinically Relevant Antibody Detection

Easy‐to‐use platforms for rapid antibody detection are likely to improve molecular diagnostics and immunotherapy monitoring. However, current technologies require multi‐step, time‐consuming procedures that limit their applicability in these fields. Herein, we demonstrate effective molarity‐driven electrochemical DNA‐based detection of target antibodies. We show a highly selective, signal‐on DNA‐based sensor that takes advantage of antibody‐binding‐induced increase of local concentration to detect clinically relevant antibodies in blood serum. The sensing platform is modular, rapid, and versatile and allows the detection of both IgG and IgE antibodies. We also demonstrate the possible use of this strategy for the monitoring of therapeutic monoclonal antibodies in body fluids. Our approach highlights the potential of harnessing effective molarity for the design of electrochemical sensing strategies.     

An electron density based analysis to establish the electronic adiabaticity of proton coupled electron transfer reactions

Electrons and protons are the main actors in play in proton coupled electron transfer (PCET) reactions, which are fundamental in many biological (i.e., photosynthesis and enzymatic reactions) and electrochemical processes. The mechanism, energetics and kinetics of PCET reactions are strongly controlled by the coupling between the transferred electrons and protons. Concerted PCET reactions are classified according to the electronical adiabaticity degree of the process. To discriminate among different mechanisms, we propose a new analysis based on the use of electron density based indexes. We choose, as test case, the 3-Methylphenoxyl/phenol system in two different conformations to show how the proposed analysis is a suitable tool to discriminate between the different degree of adiabaticity of PCET processes. The very low computational cost of this procedure is extremely promising to analyze and provide evidences of PCET mechanisms ruling the reactivity of many biological and catalytic systems.     

The Glucosamine-derivative NAPA Suppresses MAPK Activation and Restores Collagen Deposition in Human Diploid Fibroblasts Challenged with Environmental Levels of UVB

The ultraviolet (UV) component of solar radiation is the driving force of life on earth, but it can cause photoaging and skin cancer. In this study, we investigated the effects of the glucosamine-derivative 2-(N-Acetyl)-L-phenylalanylamido-2-deoxy-β-D-glucose (NAPA) on human primary fibroblasts (FBs) stimulated in vitro with environmental levels of UVB radiation. FBs were irradiated with 0.04 J cm⁻² UVB dose, which resulted a mild dosage as shown by the cell viability and ROS production measurement. This environmental UVB dose induced activation of MAP kinase ERK 1/2, the stimulation of c-fos and at lower extent of c-jun, and in turn AP-1-dependent up-regulation of pro-inflammatory factors IL-6 and IL-8 and suppression of collagen type I expression. On the contrary, 0.04 J cm⁻² UVB dose was not able to stimulate metalloprotease production. NAPA treatment was able to suppress the up-regulation of IL-6 and IL-8 via the inhibition of MAP kinase ERK phosphorylation and the following AP-1 activation, and was able to attenuate the collagen type I down-regulation induced by the UVBs. Taken together, our results show that NAPA, considering its dual action on suppression of inflammation and stimulation of collagen type I production, represents an interesting candidate as a new photoprotective and photorepairing agents.     

Phase-space approach to dynamical density functional theory

The authors consider a system of interacting particles subjected to Langevin inertial dynamics and derive the governing time-dependent equation for the one-body density. They show that, after suitable truncations of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy, and a multiple time scale analysis, they obtain a self-consistent equation involving only the one-body density. This study extends to arbitrary dimensions previous work on a one-dimensional fluid and highlights the subtleties of kinetic theory in the derivation of dynamical density functional theory.     

Effect of the quantum zero-point atomic motion on the optical and electronic properties of diamond and trans-polyacetylene

The quantum zero-point motion of the carbon atoms is shown to induce strong effects on the optical and electronic properties of diamond and trans-polyacetylene, a conjugated polymer. By using an ab initio approach, we interpret the subgap states experimentally observed in diamond in terms of entangled electron-phonon states. These states also appear in trans-polyacetylene causing the formation of strong structures in the band structure that even call into question the accuracy of the band theory. This imposes a critical revision of the results obtained for carbon-based nanostructures by assuming the atoms frozen in their equilibrium positions.     

X-ray magnetic circular dichroism measurements in Ni up to 200 GPa: resistant ferromagnetism

The structural stability of fcc Ni over a very large pressure range offers a unique opportunity to experimentally investigate how magnetism is modified by simple compression. K-edge x-ray magnetic circular dichroism (XMCD) shows that fcc Ni is ferromagnetic up to 200 GPa, contradicting recent predictions of an abrupt transition to a paramagnetic state at 160 GPa. Density functional theory calculations point out that the pressure evolution of the K-edge XMCD closely follows that of the p projected orbital moment rather than that of the total spin moment. The disappearance of magnetism in Ni is predicted to occur above 400 GPa.     

Varieties of interlaced bilattices

The paper contains some algebraic results on several varieties of algebras having an (interlaced) bilattice reduct. Some of these algebras have already been studied in the literature (for instance bilattices with conflation, introduced by M. Fitting), while others arose from the algebraic study of O. Arieli and A. Avron??s bilattice logics developed in the third author??s PhD dissertation. We extend the representation theorem for bounded interlaced bilattices (proved, among others, by A. Avron) to unbounded bilattices and prove analogous representation theorems for the other classes of bilattices considered. We use these results to establish categorical equivalences between these structures and well-known varieties of lattices.     

Temperature dependant polycrystal model application to bainitic steel behavior under tri-axial loading in the ductile–brittle transition

A polycrystal finite element (FE) model describing the temperature evolution of low carbon steel is proposed in order to forecast the local mechanical fields as a function of temperature, for bainitic microstructure submitted to tri-axial loading. The model is designed for finite strains, large lattice rotations and temperatures ranging into the brittle–ductile transition domain. The dislocation densities are the internal variables. At low temperature in Body Centred Cubic (BCC) materials, plasticity is governed by double kink nucleation of screw dislocations, whereas at high temperature, plasticity depends on interactions between mobile dislocations and the forest dislocations. In this paper, the constitutive law and the evolution of the dislocation densities are written as a function of temperature and describe low and high temperature mechanisms. The studied aggregates are built from Electron Back Scattering Diffraction (EBSD) images of real bainitic steel. The aggregate is submitted to a tri-axial loading in order to describe the material at a crack tip. Mechanical parameters are deduced from mechanical tests. The local strain and stress fields, computed for different applied loadings, present local variations which depend on temperature and on tri-axial ratio. The distribution curves of the maximal principal stresses show that heterogeneities respectively increase with temperature and decrease with tri-axial ratio. A direct application of this model provides the evaluation of the rupture probability within the aggregate, which is treated as the elementary volume in the weak link theory. A comparison with the Beremin criterion calibrated on experimental data, shows that the computed fracture probability dispersion induced by the stress heterogeneities is of the same order than the measured dispersion. Temperature and stress tri-axiality ratio effects are also investigated. It is shown that these two parameters have a strong effect on fracture owing to their influence on the heterogeneous plastic strain. These inhomogeneities can initiate cleavage fracture.     

Density and temperature in heavy-ion collisions: A test of classical and quantum approaches

Different methods to extract the temperature and density in heavy-ion collisions (HIC) are compared using a statistical model tailored to reproduce many experimental features at low excitation energy. The model assumes a sequential decay of an excited nucleus and a Fermi-gas entropy. We first generate statistical events as a function of excitation energy but stopping the decay chain at the first step. In such a condition the “exact” model temperature is determined from the Fermi-gas relation to the excitation energy. From these events, using quantum fluctuation (QF) and classical fluctuation (CF) methods for protons and neutrons, we derive temperature and density (quantum case only) of the system under consideration. Additionally, the same quantities are also extracted using the double ratio (DR) method for different particle combinations. A very good agreement between the “exact” model temperatures and quantum fluctuation temperatures is obtained. The role of the density is discussed. Classical methods give a reasonable estimate of the temperature when the density is very low, as expected. The effects of secondary decays of the excited fragments are discussed as well.     

Simple Synthesis of P1P2-Diadenosine 5′-Pyrophosphate

Pyrophosphate-linked coenzymes play essential roles in several biochemical systems. Symmetrical diadenosine-5′-pyrophosphate (Ap2A) has been synthesized from adenosine-5′-phosphate in virtually quantitative yield. The simple procedure is carried out in anhydrous pyridine using adenosine phosphoromorpholidate and adenosine monophosphate bis-(tri-n-butylammonium salt) as coupling reagents.