La sécurité urbaine dans les grandes agglomérations françaises

Alors qu'au Moyen Âge les villes étaient des lieux protecteurs au sein desquelles pouvaient se réfugier les populations en cas d'agressions extérieures, elles sont peu à peu devenues des territoires propices à la montée du crime et de l'insécurité, au point qu'elles ont conditionné la création et l'organisation des forces de police. Depuis maintenant 30 ans, de nombreux quartiers périphériques des grandes agglomérations françaises sont confrontés au développement des violences anti-institutionnelles et des trafics de stupéfiants. Alors que les services de police tentent de s'adapter à ces nouvelles menaces dans un contexte de raréfaction des moyens budgétaires, les actions mises en place jusqu'à maintenant, et notamment la politique de la ville, l'ont souvent été dans un ordre dispersé, ce qui a contribué à nuire à la lisibilité et à l'efficacité des politiques publiques.En aquest article es descriu com gradualment les ciutats franceses han passat de ser llocs segurs i protegits de les agressions externes durant l'època medieval a ser territoris propicis a una creixent delinqüència i inseguretat on, especialment durant els últims 30 anys i en els suburbis de les grans ciutats, han sorgit nous reptes i amenaces que s'han d'afrontar sovint sense prou recursos.En este artículo se describe como gradualmente las ciudades francesas han pasado de ser lugares seguros y protegidos de las agresiones externas durante la época medieval a ser territorios propicios a una creciente delincuencia e inseguridad dónde, especialmente durante los últimos 30 años y en los suburbios de las grandes ciudades, han surgido nuevos retos y amenazas que se han de afrontar a menudo sin suficientes recursos suficientes.This article describes as the French cities, gradually, have happened to be safe places and protected of the external assaults during the mediaeval period to be favorable territories to an increasing delinquency and insecurity where, especially during the last 30 years and in the suburbs of the big cities, have arisen new challenges and threats that often have to be faced without sufficient resources

Realizing a Kondo-Correlated State with Ultracold Atoms

We propose a novel realization of Kondo physics with ultracold atomic gases. It is based on a Fermi sea of two different hyperfine states of one atom species forming bound states with a different species, which is spatially confined in a trapping potential. We show that different situations displaying Kondo physics can be realized when Feshbach resonances between the species are tuned by a magnetic field and the trapping frequency is varied. We illustrate that a mixture of $^{40}K$ and $^{23}Na$ atoms can be used to generate a Kondo-correlated state and that momentum resolved radio frequency spectroscopy can provide unambiguous signatures of the formation of Kondo resonances at the Fermi energy. We discuss how tools of atomic physics can be used to investigate open questions for Kondo physics, such as the extension of the Kondo screening cloud.Physic

Sliding tethered ligands add topological interactions to the toolbox of ligand-receptor design

International audienceAdhesion in the biological realm is mediated by specific lock-and-key interactions between ligand-receptor pairs. These complementary moieties are ubiquitously anchored to substrates by tethers that control the interaction range and the mobility of the ligands and receptors, thus tuning the kinetics and strength of the binding events. Here we add sliding anchoring to the toolbox of ligand-receptor design by developing a family of tethered ligands for which the spacer can slide at the anchoring point. Our results show that this additional sliding degree of freedom changes the nature of the adhesive contact by extending the spatial range over which binding may sustain a significant force. By introducing sliding tethered ligands with self-regulating length, this work paves the way for the development of versatile and reusable bio-adhesive substrates with potential applications for drug delivery and tissue engineering

Physically stimulated nanotheranostics for next generation cancer therapy: Focus on magnetic and light stimulations

Physically or externally stimulated nanostructures often employ multimodality and show encouraging results at preclinical stage in cancer therapy. Specially designed smart nanostructures such as hybrid nanostructures are responsive to external physical stimuli such as light, magnetic field, electric, ultrasound, radio frequency, X-ray, etc. These physically responsive nanostructures have been widely explored as nonconventional innovative “nanotheranostics” in cancer therapies. Physically stimulated (particularly magnetic and light) nanotheranostics provide a unique combination of important properties to address key challenges in modern cancer therapy: (i) an active tumor targeting mechanism of therapeutic drugs driven by a physical force rather than passive antibody matching, (ii) an externally/remotely controlled drugs on-demand release mechanism, and (iii) a capability for advanced image guided tumor therapy and therapy monitoring. Although primarily addressed to the scientific community, this review offers valuable and accessible information for a wide range of readers interested in the current technological progress with direct relevance to the physics, chemistry, biomedical field, and theranostics. We herein cover magnetic and light-triggered modalities currently being developed for nonconventional cancer treatments. The physical basis of each modality is explained; so readers with a physics or, materials science background can easily grasp new developments in this field

Dynamics of Photoinduced Interfacial Electron Transfer and Charge Transport in Dye-Sensitized Mesoscopic Semiconductors

Molecular systems designed for the conversion of solar energy offer ideal models in the study of the kinetics of light-induced electron transfer at surfaces. Due to their high porosity, nanocrystalline oxide semiconductor films allow investigations of interfacial and lateral charge transfer processes that are barely detectable on flat surfaces. Although it has proven to be very promising, the redox photochemistry of the metal oxide I molecular monolayer I electrolyte interface is still a largely unexplored scientific domain, offering huge potential for investigation and exploitation of physical and chemical processes. Carrier trapping and charge transport are also key to the efficiency of molecular photonic devices. Carrier dynamics and transport in unconventional media are studied utilizing THz time domain spectroscopy. We summarize here some aspects of the work currently carried out in these fields as part of our continued effort in the fundamental study of the dynamics of photoinduced electron transfer processes

Free Water in White Matter Differentiates Mci and ad From Control Subjects

Recent evidence shows that neuroinflammation plays a role in many neurological diseases including mild cognitive impairment (MCI) and Alzheimer\u27s disease (AD), and that free water (FW) modeling from clinically acquired diffusion MRI (DTI-like acquisitions) can be sensitive to this phenomenon. This FW index measures the fraction of the diffusion signal explained by isotropically unconstrained water, as estimated from a bi-tensor model. In this study, we developed a simple but powerful whole-brain FW measure designed for easy translation to clinical settings and potential use as a priori outcome measure in clinical trials. These simple FW measures use a safe white matter (WM) mask without gray matter (GM)/CSF partial volume contamination

Resistance to a protein farnesyltransferase inhibitor in Plasmodium falciparum

The post-translational farnesylation of proteins serves to anchor a subset of intracellular proteins to membranes in eukaryotic organisms and also promotes protein-protein interactions. Inhibition of protein farnesyltransferase (PFT) is lethal to the pathogenic protozoa Plasmodium falciparum. Parasites were isolated that were resistant to BMS-388891, a tetrahydroquinoline (THQ) PFT inhibitor. Resistance was associated with a 12-fold decrease in drug susceptibility. Genotypic analysis revealed a single point mutation in the beta subunit in resistant parasites. The resultant tyrosine 837 to cysteine alteration in the beta subunit corresponded to the binding site for the THQ and peptide substrate. Biochemical analysis of Y837C-PFT demonstrated a 13-fold increase in BMS-388891 concentration necessary for inhibiting 50% of the enzyme activity. These data are consistent with PFT as the target of BMS-388891 in P. falciparum and suggest that PFT inhibitors should be combined with other antimalarial agents for effective therapy

Mouse Heterochromatin Adopts Digital Compaction States without Showing Hallmarks of HP1-Driven Liquid-Liquid Phase Separation

Mouse cells package heterochromatin into compact foci. Erdel et al. show that these foci lack hallmarks of liquid droplets and rather resemble collapsed polymer globules. Their size, accessibility, and compaction are independent of HP1. They can adopt two distinct folding states that possibly represent the fundamental modes of chromatin compaction