Integrated microring resonator sensor arrays for labs-on-chips

Planar waveguide optical ring resonators have shown great potential as compact and sensitive biochemical sensors. Advances in integrated optics based on Si technologies have allowed researchers to integrate multiple micron-sized ring resonator sensors with other optical and fluidic functions on Si chips using mass production techniques. Recent demonstrations of clinically relevant analyte detection by MRR sensor arrays have moved this technology closer to commercialization. Here, a survey of the development of microring sensor arrays for lab-on-a-chip applications is presented and illustrated with state-of-the-art examples.     

Insights into molecular recognition of Lewis(X) mimics by DC-SIGN using NMR and molecular modelling

In this work, we have studied in detail the binding of two α-fucosylamide-based mimics of Lewis(X) to DC-SIGN ECD (ECD = extracellular domain) using STD NMR and docking. We have concluded that the binding mode occurs mainly through the fucose moiety, in the same way as Lewis(X). Similarly to other mimics containing mannose or fucose previously studied, we have shown that both compounds bind to DC-SIGN ECD in a multimodal fashion. In this case, the main contact is the interaction of two hydroxyl groups one equatorial and the other one axial (O3 and O4) of the fucose with the Ca(2+) as Lewis(X) and similarly to mannose-containing mimics (in this case the interacting groups are both in the equatorial position). Finally, we have measured the K(D) of one mimic that was 0.4 mM. Competitive STD NMR experiments indicate that the aromatic moiety provides additional binding contacts that increase the affinity.     

Balanced split sets and Hamilton�CJacobi equations

We study the singular set of solutions to Hamilton?CJacobi equations with a Hamiltonian independent of u. In a previous paper, we proved that the singular set is what we called a balanced split locus. In this paper, we find and classify all balanced split loci, identifying the cases where the only balanced split locus is the singular locus, and the cases where this does not hold. This clarifies the relationship between viscosity solutions and the classical approach of characteristics, providing equations for the singular set. Along the way, we prove more structure results about the singular sets.     

Numerical schemes for a size-structured cell population model with equal fission

We study numerically the evolution of a size-structured cell population model, with finite maximum individual size and minimum size for mitosis. We formulate two schemes for the numerical solution of such a model. The schemes are analysed and optimal rates of convergence are derived. Some numerical experiments are also reported to demonstrate the predicted accuracy of the schemes. We also consider the behaviour of the methods with respect to the different discontinuities that appear in the solution to the problem and the stable size distribution. In addition, the numerical schemes are used to study asynchronous exponential growth.     

Mutual Information in Conjugate Spaces for Neutral Atoms and Ions

The discrepancy among one-electron and two-electron densities for diverse N-electron atomss, enclosing neutral systems (with nuclear charge Z=N) and charge-one ions (|N−Z|=1), is quantified by means of mutual information, I, and Quantum Similarity Index, QSI, in the conjugate spaces position/momentum. These differences can be interpreted as a measure of the electron correlation of the system. The analysis is carried out by considering systems with a nuclear charge up to Z=103 and singly charged ions (cations and anions) as far as N=54. The interelectronic correlation, for any given system, is quantified through the comparison of its double-variable electron pair density and the product of the respective one-particle densities. An in-depth study along the Periodic Table reveals the importance, far beyond the weight of the systems considered, of their shell structure.     

The S(E) factor of7Li(p, γ)8Be and consequences for S(E) extrapolation in7Be(p, γ0)8B

Excitation functions and forward-backward anisotropies have been measured for the⁷Li(p, )⁸Be capture reaction over the proton energy rangeE _p =100 to 1500 keV, using a 4 summing crystal and Ge(Li) detectors, respectively. The data show at all energies the presence of El and M1 capture amplitudes arising from the direct capture (DC) process and theE _R =441 and 1030 keV resonances, respectively. Due to the observed DC process, the present data increase significantly the reaction rates (up to a factor of 110) compared to values given in the compilation. The data and their analyses remove the recent criticism on DC model calculations, which had implied a significant reduction in the extrapolated S(E) factor for⁷Be(p,)B and thus in the predicted flux of high-energy solar neutrinos; thus, the solar neutrino problem is still with us.Supported in part by the Deutsche Forschungsgemeinschaft (Ro429/21-3 and Ro429/21-4) and the German-Hungarian Collaboration (X238.6 and OTKA3808)     

The N(p,γ)O low-energy S-factor

The ¹⁴N(p,γ)¹⁵O low-energy S-factor is analyzed using the R-matrix model. We find that the g.s. contribution is less than previously reported. The S-factor is mainly given by the 6.79 MeV state contribution which is determined by its asymptotic normalization constant (ANC). Consequently, the S-factor at zero energy is lower by a factor of 1.7 compared to the values given in recent compilations. This result may affect the nucleosynthesis and time scale evolution in massive stars. New measurements of the ¹⁴N(p,γ)¹⁵O cross section over a wide energy range, and especially at low energies, are highly desirable. Significant improvement could be also obtained from the ANC measurement of the 6.79 MeV state.     

Molecular Recognition of Natural and Non-Natural Substrates by Cellodextrin Phosphorylase from Ruminiclostridium Thermocellum Investigated by NMR Spectroscopy

β-1→4-Glucan polysaccharides like cellulose, derivatives and analogues, are attracting attention due to their unique physicochemical properties, as ideal candidates for many different applications in biotechnology. Access to these polysaccharides with a high level of purity at scale is still challenging, and eco-friendly alternatives by using enzymes in vitro are highly desirable. One prominent candidate enzyme is cellodextrin phosphorylase (CDP) from Ruminiclostridium thermocellum, which is able to yield cellulose oligomers from short cellodextrins and α-d -glucose 1-phosphate (Glc-1-P) as substrates. Remarkably, its broad specificity towards donors and acceptors allows the generation of highly diverse cellulose-based structures to produce novel materials. However, to fully exploit this CDP broad specificity, a detailed understanding of the molecular recognition of substrates by this enzyme in solution is needed. Herein, we provide a detailed investigation of the molecular recognition of ligands by CDP in solution by saturation transfer difference (STD) NMR spectroscopy, tr-NOESY and protein-ligand docking. Our results, discussed in the context of previous reaction kinetics data in the literature, allow a better understanding of the structural basis of the broad binding specificity of this biotechnologically relevant enzyme.     

Unveiling the “Three‐Finger Pharmacophore” Required for p53–MDM2 Inhibition by Saturation‐Transfer Difference (STD) NMR Initial Growth‐Rates Approach

Inhibitors of the p53‐MDM2 protein–protein interaction are emerging as a new and validated approach to treating cancer. Herein, we describe the synthesis and inhibitory evaluation of a series of isoquinolin‐1‐one analogues, and highlight the utility of an initial growth‐rates saturation‐transfer difference (STD) NMR approach supported by protein–ligand docking to investigate p53‐MDM2 inhibition. The approach is illustrated by the study of compound 1 , providing key insights into the binding mode of this kind of MDM2 ligands and, more importantly, readily unveiling the previously proposed three‐finger pharmacophore requirement for p53‐MDM2 inhibition.     

Assessing the effect of advertising expenditures upon sales: A Bayesian structural time series model

We propose a robust implementation of the Nerlove‐Arrow model using a Bayesian structural time series model to explain the relationship between advertising expenditures of a countrywide fast‐food franchise network with its weekly sales. Due to the flexibility and modularity of the model, it is well suited to generalization to other markets or situations. Its Bayesian nature facilitates incorporating a priori information reflecting the manager's views, which can be updated with relevant data. This aspect of the model will be used to support the decision of the manager on the budget scheduling of the advertising firm across time and channels.