Molecular Kondo resonance in atomic Fermi gases

The usual Kondo effect is associated with the formation of a many-body ground state that contains a quantum-mechanical entanglement between a (localized) fermion and the free fermions. We show, however, that also a bosonic form of the Kondo effect can occur in degenerate atomic Fermi gases near a Feshbach resonance, if the energy of the diatomic molecular level associated with the Feshbach resonance approaches twice the Fermi energy of the atoms.     

Valorization of Winemaking By-Products as a Novel Source of Antibacterial Properties: New Strategies to Fight Antibiotic Resistance

The emergence of antibiotic-resistance in bacteria has limited the ability to treat bacterial infections, besides increasing their morbidity and mortality at the global scale. The need for alternative solutions to deal with this problem is urgent and has brought about a renewed interest in natural products as sources of potential antimicrobials. The wine industry is responsible for the production of vast amounts of waste and by-products, with associated environmental problems. These residues are rich in bioactive secondary metabolites, especially phenolic compounds. Some phenolics are bacteriostatic/bactericidal against several pathogenic bacteria and may have a synergistic action towards antibiotics, mitigating or reverting bacterial resistance to these drugs. Complex phenolic mixtures, such as those present in winemaking residues (pomace, skins, stalks, leaves, and especially seeds), are even more effective as antimicrobials and could be used in combined therapy, thereby contributing to management of the antibiotic resistance crisis. This review focuses on the potentialities of winemaking by-products, their extracts, and constituents as chemotherapeutic antibacterial agents.     

Fragment‐Based Discovery of a Dual pan‐RET/VEGFR2 Kinase Inhibitor Optimized for Single‐Agent Polypharmacology

Oncogenic conversion of the RET (rearranged during transfection) tyrosine kinase is associated with several cancers. A fragment‐based chemical screen led to the identification of a novel RET inhibitor, Pz‐1. Modeling and kinetic analysis identified Pz‐1 as a type II tyrosine kinase inhibitor that is able to bind the “DFG‐out” conformation of the kinase. Importantly, from a single‐agent polypharmacology standpoint, Pz‐1 was shown to be active on VEGFR2, which can block the blood supply required for RET‐stimulated growth. In cell‐based assays, 1.0 nM of Pz‐1 strongly inhibited phosphorylation of all tested RET oncoproteins. At 1.0 mg kg^?1 day^?1 per os, Pz‐1 abrogated the formation of tumors induced by RET‐mutant fibroblasts and blocked the phosphorylation of both RET and VEGFR2 in tumor tissue. Pz‐1 featured no detectable toxicity at concentrations of up to 100.0 mg kg^?1, which indicates a large therapeutic window. This study validates the effectiveness and usefulness of a medicinal chemistry/polypharmacology approach to obtain an inhibitor capable of targeting multiple oncogenic pathways.     

Ultrafast all‐optical order‐to‐chaos transition in silicon photonic crystal chips

The interaction of light with nanostructured materials provides exciting new opportunities for investigating classical wave analogies of quantum phenomena. A topic of particular interest forms the interplay between wave physics and chaos in systems where a small perturbation can drive the behavior from the classical to chaotic regime. Here, we report an all‐optical laser‐driven transition from order to chaos in integrated chips on a silicon photonics platform. A square photonic crystal microcavity at telecom wavelengths is tuned from an ordered into a chaotic regime through a perturbation induced by ultrafast laser pulses in the ultraviolet range. The chaotic dynamics of weak probe pulses in the near infrared is characterized for different pump‐probe delay times and at various positions in the cavity, with high spatial accuracy. Our experimental analysis, confirmed by numerical modelling based on random matrices, demonstrates that nonlinear optics can be used to control reversibly the chaotic behavior of light in optical resonators.

     

Isolation of NO(3)(-)-N as 1-phenylazo-2-naphthol (Sudan-1) for measurement of delta(15)N

The conversion of nitrate (NO(3)(-)) to 1-phenylazo-2-naphthol (Sudan-1) has been examined as a method for natural abundance measurement of delta(15)N of NO(3)(-). The reaction results in dilution of NO(3)(-)-N with only one reagent-derived N and the product is readily concentrated from dilute samples by reverse phase chromatography. There is systematic isotopic fractionation during the reaction, but this can be allowed for by analysing known NO(3)(-) standards along with each sample set. Sudan-1 prepared from surface water samples containing approximately 50 &mgr;g NO(3)(-)-N can be analysed by automated continuous flow isotope ratio mass spectrometry with a precision of 0.2 per thousand (one standard deviation) and the accuracy is not affected by interference from other nitrogenous species in the sample or reagents. Copyright 1999 John Wiley & Sons, Ltd.     

Soot particle size distribution measurements in a turbulent ethylene swirl flame

There is a need to better understand particle size distributions (PSDs) from turbulent flames from a theoretical, practical and even regulatory perspective. Experiments were conducted on a sooting turbulent non-premixed swirled ethylene flame with secondary (dilution) air injection to investigate exhaust and in-burner PSDs measured with a Scanning Mobility Particle Sizer (SMPS) and soot volume fractions (f_v) using extinction measurements. The focus was to understand the effect of systematically changing the amount and location of dilution air injection on the PSDs and f_v inside the burner and at the exhaust. The PSDs were also compared with planar Laser Induced Incandescence (LII) calibrated against the average f_v. LII provides some supplemental information on the relative soot amounts and spatial distribution among the various flow conditions that helps interpret the results. For the flame with no air dilution, f_v drops gradually along the centreline of the burner towards the exhaust and the PSD shows a shift from larger particles to smaller. However, with dilution air f_v reduces sharply where the dilution jets meet the burner axis. Downstream of the dilution jets f_v reduces gradually and the PSDs remain unchanged until the exhaust. At the exhaust, the flame with no air dilution shows significantly more particles with an f_v one to two orders of magnitude greater compared to the Cases with dilution. This dataset provides insights into soot spatial and particle size distributions within turbulent flames of relevance to gas turbine combustion with differing dilution parameters and the effect dilution has on the particle size. Additionally, this work measures f_v using both ex situ and in situ techniques, and highlights the difficulties associated with comparing results across the two. The results are useful for validating advanced models for turbulent combustion.     

Groups whose Proper Subgroups of Infinite Rank Have a Transitive Normality Relation

A group G is called a T-group if all its subnormal subgroups are normal, and G is a ${\bar{T}}$ -group if every subgroup of G has the property T. It is proved here that if G is a locally soluble group whose proper subgroups of infinite rank have the T-property, then either G is a ${\bar{T}}$ -group or it has finite rank.     

A note on groups of infinite rank with modular subgroup lattice

It is proved that if \(G\) is a (generalized) soluble group of infinite rank in which all proper subgroups of infinite rank are permodular, then the subgroup lattice of \(G\) is permodular. As a consequence of this theorem, we obtain shorter proofs for corresponding known results concerning normal or permutable subgroups of groups of infinite rank.     

An estimate on the large N behavior of Z N spin systems in two dimensions

We consider spin systems in two dimensions having the discrete symmetry group Z _N . We give a bound on the spontaneous magnetization for such systems which reduces to the classical Mermin-Wager argument as N goes to infinity. Research supported in part by NSF PHY 78-23952.