Impact of amoxicillin and oral amoxicillin-clavulanic acid defined daily doses on consumption indicators.

OBJECTIVE: To measure the impact of the differences between recommended daily average maintenance doses and defined daily doses on antimicrobial consumption indicators (amoxicillin+amoxicillin-clavulanic acid). MATERIAL AND METHODS: We calculated the impact of the antibacterial agent switch or de-escalation and reviewed the consumption indicators of our French hospital with defined daily doses (DDD) of 3g. We also applied these DDDs to French and European community setting indicators in private practice. RESULTS: We observed a modification in trend consumption indicators over a 10-year period: indicator stability for our hospital (-0.32% versus +5.45%), decrease for French community indicators (-9.9% versus +6.7%). The recalculated 2015 data for European community indicators showed France as the 9th largest European consumer (versus 4th position before). CONCLUSION: DDDs must be modified to have appropriate indicators to evaluate antimicrobial stewardship programs and to penalize prescriptions favoring the emergence of resistant pathogens.

Strong Coupling between Self-Assembled Molecules and Surface Plasmon Polaritons.

We experimentally demonstrate strong coupling between self-assembled PTCDI-C7 organic molecules and the electromagnetic mode generated by surface plasmon polaritons (SPPs). The system consists of a dense self-assembly of ordered molecules evaporated directly on a thin gold film, which stack perpendicularly to the metal surface to form H-aggregates, without a host matrix. Experimental wavevector-resolved reflectance spectra show the formation of hybrid states that display a clear anticrossing, attesting the strong coupling regime with a Rabi splitting energy of ΩR ≃ 102 meV at room temperature. We demonstrate that the strength of the observed strong coupling regime derives from the high degree of organization of the dense layers of self-assembled molecules at the nanoscale that results in the concentration of the oscillator strength in a charge-transfer Frenkel exciton, with a dipole moment parallel to the direction of the maximum electric field. We compare our results to numerical simulations of a transfer matrix model and reach good qualitative agreement with the experimental findings. In our nanophotonic system, the use of self-assembled molecules opens interesting prospects in the context of strong coupling regimes with molecular systems.

Quality improvement program of adult urinary tract infection management: Review and impact.

OBJECTIVE: A quality improvement program for adult urinary tract infection management was established to avoid unnecessary antibiotic treatment and to promote adequate prescription, associated with financial and time savings. METHODS: Management was integrated into a three-step approach: clinical diagnosis, bacteriological diagnosis, and therapeutic decision. For each step, areas for improvement were prioritized and implemented through corrective measures and key messages, measured by indicators. This program was applied to the whole hospital, which includes an emergency department and hospital units (672 beds). RESULTS: The diffusion of new recommendations on clinical diagnosis helped limit the use of Urine Dipstick Tests (UDT) and identify situations requiring the prescription of urine cytobacteriological test (UCBE) and antibiotic treatment: decreased annual consumption of UDTs (34%) and UCBEs (25%). The implementation of a new sampling system for UCBEs was associated with a 21% increase in conclusive analysis. Results of antimicrobial susceptibility testing were also optimized. Trainings on the proper use of antibiotics led to a 5.0% decline in global consumption. Only 23 antibiotic prescriptions for UTI resulted in pharmaceutical advice to prescribers in 2014. CONCLUSION: The program is part of a practice improvement strategy. Integrating the management of urinary tract infections into a global process helped improve each step of patient management.

2D self-assembly of phenylene-vinylene tectons at the liquid-highly oriented pyrolytic graphite interface: from chain length effects to anisotropic guest-host dynamics.

Here we report the synthesis and characterization of a series of new phenylene-vinylene tectons. The study by scanning tunneling microscopy of their supramolecular self-assembly at the interface between a phenyloctane solution and highly oriented pyrolytic graphite  demonstrates that variation of concentration and length of alkyl chains led to the formation of different networks, a compact one and a nanoporous one, with a fine control of the lattice parameters. The study of guest-host properties of the nanoporous network revealed a selectivity toward guest compounds according to their shape and size. Moreover, the statistical analysis of pore-to-pore guest dynamics evidences an anisotropic diffusion process.

High resolution scanning near field mapping of enhancement on SERS substrates: comparison with photoemission electron microscopy.

The need for a dedicated spectroscopic technique with nanoscale resolution to characterize SERS substrates pushed us to develop a proof of concept of a functionalized tip-surface enhanced Raman scattering (FTERS) technique. We have been able to map hot spots on semi-continuous gold films; in order to validate our approach we compare our results with photoemission electron microscopy (PEEM) data, the complementary electron microscopy tool to map hot spots on random metallic surfaces. Enhanced Raman intensity maps at high spatial resolution reveal the localisation of hotspots at gaps for many neighboring nanostructures. Finally, we compare our findings with theoretical simulations of the enhancement factor distribution, which confirms a dimer effect as the dominant origin of hot spots.

The electronic properties of mixed valence hydrated europium chloride thin film.

We investigate the electronic properties of a model mixed-valence hydrated chloride europium salt by means of high resolution photoemission spectroscopy (HRPES) and resonant photoemission spectroscopy (RESPES) at the Eu 3d → 4f and 4d → 4f transitions. From the HRPES spectra, we have determined that the two europium oxidation states are homogeneously distributed in the bulk and that the hydrated salt film is exempt from surface mixed valence transition. From the RESPES spectra, the well separated resonant contributions characteristic of divalent and trivalent europium species (4f(6) and 4f(7) final states, respectively) are accurately extracted and quantitatively determined from the resonant features measured at the two edges. The partial absorption yield spectra, obtained by integrating the photoemission intensity in the valence-band region, can be well reproduced by atomic multiplet calculation at the M(4,5) (3d-4f) absorption edge and by an asymmetric Fano-like shape profile at the N(4,5) (4d-4f) absorption edge. The ratio of Eu(2+) and Eu(3+) species measured at the two absorption edges matches with the composition of the mixed valence europium salt as determined chemically. We have demonstrated that the observed spectroscopic features of the mixed valence salt are attributed to the mixed-valence ground state rather than surface valence transition. HRPES and RESPES spectra provide reference spectra for the study of europium salts and their derivatives.

N-phenyl-carbazole-based two-photon fluorescent probes: strong sequence dependence of the duplex vs quadruplex selectivity.

Herein we report on the synthesis and DNA recognition properties of a series of three N-phenyl carbazole-based light-up probes initially designed for two-photon absorption. The vinylic derivatives (Cbz-2Py, Cbz-3Py) display strong fluorescence enhancement when bound to various duplex- and quadruplex-forming oligonucleotides whereas the oxazole derivative is not fluorescent in DNA. Determination of affinity constants by fluorimetric titrations evidenced that Cbz-2Py has a clear preference for AT-rich duplex structures. Circular Dichroism (CD) measurements confirmed the sequence-dependent binding of this compound and suggest insertion in the minor groove as shown by a strong induced CD (ICD) signal and further supported by molecular modeling. Altogether the data indicate that duplex vs quadruplex selectivity of the dyes is strongly dependent on the sequence of the duplex. Finally, the dyes exhibit high two-photon absorption cross-sections (up to 540GM in glycerol) and allow a fine and bright staining of nuclear DNA with low background fluorescence as shown by one and two-photon confocal microscopy imaging of fixed cells.

New triarylamine-based far-red DNA stainers with high two-photon absorption properties.

A series of red emitting vinyl-triphenyamines (TP) have been synthesized and evaluated for their two photon absorption (2PA) properties. These compounds are virtually non fluorescent in the free state but exhibit a bright red fluorescence upon binding to double-stranded DNA, both in one- and two-photon absorption. This feature allows one- and two-photon confocal imaging in cells of nuclear DNA with an excellent contrast. Derivatizable analogues for covalent bioconjugation to oligonucleotides are described and variation on the structure is discussed.

Coupled plasmon modes in an ordered hexagonal monolayer of metal nanoparticles: a direct observation.

We report on the experimental observation of STM-induced photon emission in ultrahigh vacuum on a network of 4-nm silver spheres. The spheres are covered by a dielectric, electrically insulating, organic layer and deposited on Au(111). The bias-dependent spatial distribution of the photon emission rates reveals the electric-field distribution of the different coupled plasmon modes in this model.

Interband electronic excitation-assisted atomic-scale restructuring of metal surfaces by nanosecond pulsed laser light

Interaction of high-power laser light with materials often causes irreversible damage of the near-surface region. It is shown that copper single-crystal surfaces can be patterned by laser light. Irradiation with green light produced adatoms and vacancies, which self-organized into nanoscale pyramids. This restructuring can be removed by annealing. In contrast to green light, infrared laser irradiation at equivalent absorbed energy density did not produce any structural change. This, for metallic systems, unforeseen spectral difference in laser light action points to a concerted process as the source for structural modification, which involves long-lived primary excitation of localized d-electrons through interband transition together with phonon excitation.

All-optical induction of noncentrosymmetry in a transparent nonlinear polymer rod.

What is believed to be the first evidence of an all-optical orientation of a highly transparent polymer is presented. The samples are bulk rods of poly(methyl methacrylate) grafted with paranitroaniline (PNA) obtained by use of copolymerization of methyl methacrylate (MMA) monomers mixed with grafted MMA-PNA monomers. Bulk samples were obtained after molding and polishing of the copolymer with standard techniques. Experiments show that the photoinduced second-order(1) susceptibility chi((2)) may occur through molecular reorientation following selective polar excitation of the nonlinear chromophores by simultaneous two- and three-photon absorption on the same electronic level.

Light-induced second-harmonic generation in azo-dye polymers.

The permanent all-optical poling of an azo-aromatic acrylic copolymer is experimentally demonstrated by seeding preparation in a backward phase-conjugation geometry. The microscopic mechanism involves an orientational hole burning followed by orientational redistribution caused by trans-to-cis isomerization of the azo-dye chromophores. The characteristic kinetics of monitored by second-harmonic generation.

Phase and frequency resolution of picosecond optical Kerr nonlinearities.

We report on a method aimed at measuring both the real and imaginary parts of the third-order Kerr-type nonlinear-optical susceptibility of isotropic materials. It is based on Kerr ellipsometry in which analysis of the polarization state of transmitted light between a nearly crossed polarizer and an analyzer allows separation of pump-induced dichroism and birefringence. The method provides a natural measurement of nonlinear phase retardations in angle units, without any calibration procedure. By using a white-light continuum as a probe, this property is used to get a simultaneous measurement of the nonlinear dispersion in the whole visible spectrum. It is illustrated in tetramethylsilane, where stimulated Stokes and anti-Stokes Raman contributions to the nonlinearity are observed.