Dose of colistin. a work in progress?

We thank Rashid and colleagues [1] and Honoré and colleagues [2] for their comments regarding our article on risk factors for acute kidney injury in pa- tients receiving colistin or other nephrotoxic antimi- crobials [3]. It is correct that we did not specifically report urine output in the text, but it was obviously included in the RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease) criteria reported in Table two [3]

Bloodstream yeast infections: a 15-month survey

A 15-month survey of 412 bloodstream yeast isolates from 54 Belgian hospitals was undertaken. Candida albicans was the most common species (47.3%) followed by C. glabrata (25.7%), C. parapsilosis (8.0%), C. tropicalis (6.8%) and Saccharomyces cerevisiae (5.1%). Common predisposing factors were antibacterial therapy (45%), hospitalization in intensive care units (34%), presence of in-dwelling catheters (32%), underlying cancer (23%) and major surgery (11%). Most patients had more than one predisposing factor. Fluconazole alone or in combination with another antifungal agent was the treatment of choice for 86.6% of the cases. Susceptibility testing revealed that 93.5% were susceptible to amphotericin B, 39.6% to itraconazole, 42.8% to fluconazole and 87% to voriconazole. Resistance to azoles was more common among C. glabrata isolates

The Metallicity Distribution Function of Field Stars in M31's Bulge

We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ~1.6 kpc from the galaxy's center. Using scaled-solar abundance theoretical red giant branches with a range of metallicities, we have translated the observed colors of the stars in the CMD to abundances and constructed a metallicity distribution function (MDF) for this region. The MDF shows a peak at [M/H]~0 with a steep decline at higher metallicities and a more gradual tail to lower metallicities. This is similar in shape to the MDF of the Milky Way bulge but shifted to higher metallicities by ~0.1 dex. As is the case with the Milky Way bulge MDF, a pure closed box model of chemical evolution, even with significant pre-enrichment, appears to be inconsistent with the M31 bulge MDF. However, a scenario in which an initial infall of gas enriched the bulge to an abundance of [M/H] ~ -1.6 with subsequent evolution proceeding as a closed box provides a better fit to the observed MDF. The similarity between the MDF of the M31 bulge and that of the Milky Way stands in stark contrast to the significant differences in the MDFs of their halo populations. This suggests that the bulk of the stars in the bulges of both galaxies were in place before the accretion events that occurred in the halos could influence them.Comment: 12 pages, 9 figures, accepted for publication in The Astronomical Journal, October 200

Full-wave electromagnetic modes and hybridization in nanoparticle dimers

The plasmon hybridization theory is based on a quasi-electrostatic approximation of the Maxwell’s equations. It does not take into account magnetic interactions, retardation effects, and radiation losses. Magnetic interactions play a dominant role in the scattering from dielectric nanoparticles. The retardation effects play a fundamental role in the coupling of the modes with the incident radiation and in determining their radiative strength; their exclusion may lead to erroneous predictions of the excited modes and of the scattered power spectra. Radiation losses may lead to a significant broadening of the scattering resonances. We propose a hybridization theory for non-Hermitian composite systems based on the full-Maxwell equations that, overcoming all the limitations of the plasmon hybridization theory, unlocks the description of dielectric dimers. As an example, we decompose the scattered field from silicon and silver dimers, under different excitation conditions and gap-sizes, in terms of dimer modes, pinpointing the hybridizing isolated-sphere modes behind them

[OIII] Emission and Gas Kinematics in a Lyman-alpha Blob at z ~ 3.1

We present spectroscopic measurements of the [OIII] emission line from two subregions of strong Lyman-alpha emission in a radio-quiet Lyman-alpha blob (LAB). The blob under study is LAB1 (Steidel et al. 2000) at z ~ 3.1, and the [OIII] detections are from the two Lyman break galaxies embedded in the blob halo. The [OIII] measurements were made with LUCIFER on the 8.4m Large Binocular Telescope and NIRSPEC on 10m Keck Telescope. Comparing the redshift of the [OIII] measurements to Lyman-alpha redshifts from SAURON (Weijmans et al. 2010) allows us to take a step towards understanding the kinematics of the gas in the blob. Using both LUCIFER and NIRSPEC we find velocity offsets between the [OIII] and Lyman-alpha redshifts that are modestly negative or consistent with 0 km/s in both subregions studied (ranging from -72 +/- 42 -- +6 +/- 33 km/s). A negative offset means Lyman-alpha is blueshifted with respect to [OIII], a positive offset then implies Lyman-alpha is redshifted with respect to [OIII]. These results may imply that outflows are not primarily responsible for Lyman alpha escape in this LAB, since outflows are generally expected to produce a positive velocity offset (McLinden et al. 2011). In addition, we present an [OIII] line flux upper limit on a third region of LAB1, a region that is unassociated with any underlying galaxy. We find that the [OIII] upper limit from the galaxy-unassociated region of the blob is at least 1.4 -- 2.5 times fainter than the [OIII] flux from one of the LBG-associated regions and has an [OIII] to Lyman-alpha ratio measured at least 1.9 -- 3.4 times smaller than the same ratio measured from one of the LBGs.Comment: submitted to Ap

Structure de l’écoulement tridimensionnel, turbulence et contrainte de cisaillement dans une boucle de méandre

Plusieurs facteurs contribuent à l’instabilité des berges dans les méandres, mais le rôle joué par la dynamique de l’écoulement complexe au sein de ces sites n’est pas clairement élucidé. L’objectif de cette recherche est d’examiner la dynamique de l’écoulement tridimensionnel (3D) d’une boucle de méandre en vue de déterminer les liens entre la structure de l’écoulement moyen et turbulent, la contrainte de cisaillement et l’érosion des berges. Des données de vitesse 3D ont été recueillies dans une boucle de méandre avec un vélocimètre acoustique Doppler (ADV) et un profileur acoustique Doppler conçu pour les rivières peu profondes (PC-ADP). Une comparaison entre ces deux appareils a révélé que le PC-ADP donne de bons estimés de vitesse moyenne dans un écoulement relativement simple (au centre du chenal), mais le problème de moyennage spatial le rend moins efficace dans un plan de mélange où l’écoulement est plus complexe. L’ADV est aussi supérieur au PC-ADP pour les estimés de contrainte de cisaillement et l’étude de la turbulence à petite échelle, mais ce dernier révèle mieux les patrons à grande échelle. Deux cellules d’écoulement secondaire dans le méandre ressortent nettement avec les mesures simultanées du PC-ADP. Les maxima de contrainte de cisaillement mesurée avec l’ADV par la méthode d’énergie turbulente cinétique sont situés à l’entrée du méandre lorsque le niveau est plus bas, et à la sortie du méandre lorsque le niveau augmente. Ces deux zones correspondent à des observations de décrochement de berge au site d’étude.Many factors contribute to bank instability in meanders, but the exact role played by the complex flow dynamics is not very well understood. The objective of this research is to examine the three-dimensional (3D) flow dynamics in a meander loop to determine the links between the mean and turbulent flow structure, and bank erosion. 3D velocity data were collected in a meander loop with an acoustic Doppler velocimeter (ADV) and a pulse-coherent acoustic Doppler profiler (PC-ADP). A comparison between these two devices revealed that the PC-ADP provides accurate estimates of mean velocity in a relatively simple flow (in the centre of the channel), but that it is less efficient in a complex flow field with a mixing zone due to spatial averaging problems. The ADV is also better than the PC-ADP for bed shear stress estimates and for small-scale turbulence studies, but the latter reveals large-scale structures efficiently. Two secondary cells in the meander loop are clearly seen from the simultaneous PC-ADP measurements. The maximum values of bed shear stress measured with the ADV with the turbulent kinetic energy method are located at the meander entrance when flow stage is low, and at the meander exit when flow stage increases. These two zones correspond to observations of bank failure events at the field site

Ultrafast light-induced response of photoactive yellow protein chromophore analogues

The fluorescence decays of several analogues of the photoactive yellow protein (PYP) chromophore in aqueous solution have been measured by femtosecond fluorescence up-conversion and the corresponding time-resolved fluorescence spectra have been reconstructed. The native chromophore of PYP is a thioester derivative of p-coumaric acid in its trans deprotonated form. Fluorescence kinetics are reported for a thioester phenyl analogue and for two analogues where the thioester group has been changed to amide and carboxylate groups. The kinetics are compared to those we previously reported for the analogues bearing ketone and ester groups. The fluorescence decays of the full series are found to lie in the 1–10 ps range depending on the electron-acceptor character of the substituent, in good agreement with the excited-state relaxation kinetics extracted from transient absorption measurements. Steady-state photolysis is also examined and found to depend strongly on the nature of the substituent. While it has been shown that the ultrafast light-induced response of the chromophore in PYP is controlled by the properties of the protein nanospace, the present results demonstrate that, in solution, the relaxation dynamics and pathway of the chromophore is controlled by its electron donor–acceptor structure: structures of stronger electron donor–acceptor character lead to faster decays and less photoisomerisation

A genetic variant of the sperm-specific SLO3 K+ channel has altered pH and Ca2+ sensitivities

To fertilize an oocyte, sperm must first undergo capacitation in which the sperm plasma membrane becomes hyperpolarized via activation of potassium (K(+)) channels and resultant K(+) efflux. Sperm-specific SLO3 K(+) channels are responsible for these membrane potential changes critical for fertilization in mouse sperm, and they are only sensitive to pH i However, in human sperm, the major K(+) conductance is both Ca(2+)- and pH i -sensitive. It has been debated whether Ca(2+)-sensitive SLO1 channels substitute for human SLO3 (hSLO3) in human sperm or whether human SLO3 channels have acquired Ca(2+) sensitivity. Here we show that hSLO3 is rapidly evolving and reveal a natural structural variant with enhanced apparent Ca(2+) and pH sensitivities. This variant allele (C382R) alters an amino acid side chain at a principal interface between the intramembrane-gated pore and the cytoplasmic gating ring of the channel. Because the gating ring contains sensors to intracellular factors such as pH and Ca(2+), the effectiveness of transduction between the gating ring and the pore domain appears to be enhanced. Our results suggest that sperm-specific genes can evolve rapidly and that natural genetic variation may have led to a SLO3 variant that differs from wild type in both pH and intracellular Ca(2+) sensitivities. Whether this physiological variation confers differences in fertility among males remains to be established.info:eu-repo/semantics/publishe