Mode I fatigue of the carbon fiber-reinforced plastic—concrete interface bond

Experimental Techniques - As the reinforced concrete infrastructure continues to decline, the engineering community is turning to rehabilitative methods as cost effective alternatives to...     

Determination of temperature by stimulated raman scattering of molecular nitrogen,oxygen, and carbon dioxide

We have determined the temperature from SRS spectra of N₂-N₂, N₂-CO₂, O₂-O₂, and CO₂-CO₂ recorded in wide pressure and temperature ranges. The fitting procedure takes simultaneously into account the Dicke effect and motional narrowing. We have quantified the accuracy of the MEG and ECS-P models for rotational relaxation. The temperature extracted from each model is compared with thermocouple measurements. The influence of vibrational broadening and shifting is discussed in detail.     

Nonequilibrium raftlike membrane domains under continuous recycling

We present a model for the kinetics of spontaneous membrane domain (raft) assembly that includes the effect of membrane recycling ubiquitous in living cells. We show that domains can have a broad power-law distribution with an average radius that scales with the 1/4 power of the domain lifetime when the line tension at the domain edges is large. For biologically reasonable recycling and diffusion rates, the average domain radius is in the tens of nm range, consistent with observations. This represents one possible link between signaling (involving rafts) and traffic (recycling) in cells. Finally, we present evidence that suggests that the average raft size may be the same for all scale-free recycling schemes.     

The Critical Fugacity for Surface Adsorption of Self-Avoiding Walks on the Honeycomb Lattice is {1+\sqrt{2}}

In 2010, Duminil-Copin and Smirnov proved a long-standing conjecture of Nienhuis, made in 1982, that the growth constant of self-avoiding walks on the hexagonal (a.k.a. honeycomb) lattice is ${\mu=\sqrt{2+\sqrt{2}}}$ . A key identity used in that proof was later generalised by Smirnov so as to apply to a general O(n) loop model with ${n\in [-2,2]}$ (the case n = 0 corresponding to self-avoiding walks). We modify this model by restricting to a half-plane and introducing a surface fugacity y associated with boundary sites (also called surface sites), and obtain a generalisation of Smirnov’s identity. The critical value of the surface fugacity was conjectured by Batchelor and Yung in 1995 to be ${y_{\rm c}=1+2/\sqrt{2-n}}$ . This value plays a crucial role in our generalized identity, just as the value of the growth constant did in Smirnov’s identity. For the case n = 0, corresponding to self-avoiding walks interacting with a surface, we prove the conjectured value of the critical surface fugacity. A crucial part of the proof involves demonstrating that the generating function of self-avoiding bridges of height T, taken at its critical point 1/μ, tends to 0 as T increases, as predicted from SLE theory.     

In silico design of peptidic inhibitors targeting estrogen receptor alpha dimer interface

Human estrogen receptor alpha (ERα), which acts as a biomarker and as a therapeutic target for breast cancers, is activated by agonist ligands and co-activator proteins. Selective estrogen receptor modulators (SERM) act as antagonists in specific tissues and tamoxifen, a SERM, has served as a drug for decades for ERα-positive breast cancers. However, the ligand-selective and tissue-specific response of ERα biological activity and the resistance to tamoxifen treatment in advanced stages of ERα-positive breast cancers underscores the need to find a ligand-independent inhibitor for ERα. Here we present a ligand-independent approach of inhibiting ERα transactivation targeting its dimerization-a key process of ERα biological activity. Using in silico techniques, we first elucidated the hydrogen bond interactions involved in dimerization and identified three interfacial sequence motifs, where sequence I (DKITD) and sequence II (QQQHQRLAQ) of one monomer form hydrogen bonding with sequence II and sequence I of the second monomer, respectively, and sequence III (LSHIRHMSNK) hydrogen bonds with the same from the second monomer. Studying the structural stability and the binding affinity of the peptides derived from these sequence motifs, we found that an extended and ARG mutated version (LQQQHQQLAQ) of sequence II can act as a suitable template for designing peptidic inhibitors. It provides additional structural stability and interacts more strongly with ERα dimer interface groove formed by helices 9 and 10/11 and prevent ERα dimerization. Our result provides a novel therapeutic designing pipeline for ligand-independent inhibition of ERα.     

A novel method for the detection of plasma jet boundaries by exploring DNA damage

The coupled-channel optical method (CCOM) is implemented in this work to study the scattering of electron on rubidium atom at 20 eV. In order to provide a realistic calculation, the continuum effect of the scattering system is accounted by incorporate an ab initio optical potential into the CCOM calculation. The differential cross sections (DCS), as well as the reduced Stokes parameters of 5p excitation are reported and compared to the available experimental and theoretical data.     

Stereochemical analysis of ferrocene and the uncertainty of fluorescence XAFS data

Methods for the quantification of statistically valid measures of the uncertainties associated with X‐ray absorption fine structure (XAFS) data obtained from dilute solutions using fluorescence measurements are developed. Experimental data obtained from 10 mM solutions of the organometallic compound ferrocene, Fe(C₅H₅)₂, are analysed within this framework and, following correction for various electronic and geometrical factors, give robust estimates of the standard errors of the individual measurements. The reliability of the refinement statistics of standard current XAFS structure approaches that do not include propagation of experimental uncertainties to assess subtle structural distortions is assessed in terms of refinements obtained for the staggered and eclipsed conformations of the C₅H₅ rings of ferrocene. Standard approaches (XFIT, IFEFFIT) give refinement statistics that appear to show strong, but opposite, preferences for the different conformations. Incorporation of experimental uncertainties into an IFEFFIT‐like analysis yield refinement statistics for the staggered and eclipsed forms of ferrocene which show a far more realistic preference for the eclipsed form which accurately reflects the reliability of the analysis. Moreover, the more strongly founded estimates of the refined parameter uncertainties allow more direct comparison with those obtained by other techniques. These XAFS‐based estimates of the bond distances have accuracies comparable with those obtained using single‐crystal diffraction techniques and are superior in terms of their use in comparisons of experimental and computed structures.     

TOF-SIMS investigation of Streptomyces coelicolor, a mycelial bacterium

Streptomyces coelicolor is a mycelial microorganism that produces several secondary metabolites, including antibiotics. The physiology of the organism has largely been investigated in liquid cultures due to ease of monitoring different physiological parameters and more homogeneous culture conditions. However, solid cultures reflect the natural physiology of the microorganism better, given that in its natural state it grows in the soil. Imaging mass spectrometry with TOF-SIMS and C₆₀⁺ primary ion beams offers a potential route to studying chemical changes at the molecular level, both intracellular and extracellular that can help in understanding the natural physiology of the microorganism. Here, we report the application of the technique for studying the lateral distribution of the chemical species detected in a population, grown in both liquid and solid cultures. The capability of the technique for studying biological systems with minimal system intervention is demonstrated.