Quasars probing intermediate redshift star-forming galaxies

We present a sample of 46 [OIII]-emitting galaxies at z<0.8 detected in the fibre spectra of quasars from the SDSS-DR7 through an automatic search procedure. We also detect [OII] and Hb emission lines from most of these galaxies in the SDSS spectra. We study both the emission and absorption properties of a sub-sample of 17 galaxies in the redshift range z=0.4-0.7, where MgII lines are covered by the SDSS spectra. The measured lower-limits on the star-formation rates of these galaxies are in the range 0.2-20 M_sun/yr. The emission line luminosities and (O/H) metallicities from R23 measured in this sample are similar to what is found in normal galaxies at these redshifts. Thus, this constitutes a unique sample of intermediate redshift star-forming galaxies where we can study the QSO absorber - galaxy connection. Strong MgII (W>1A) as well as MgI absorption lines are detected in the QSO spectra at the redshift of most of these galaxies. Strong FeII (W>1A) absorption lines are also generally detected whenever the appropriate wavelength ranges are covered. This suggests that most of these systems could be bona-fide Damped Lyman-alpha systems. We investigate various possible relations between the MgII rest equivalent widths and the emission line properties. We find a possible (2 sigma) correlation between the emission-line metallicity of the galaxies and the MgII rest equivalent width of the absorbers [truncated].Comment: 15 pages, 11 figures, 5 tables. accepted for publication in MNRA

Enhancement of seawater corrosion resistance in copper using acetone-derived graphene coating

We show that acetone-derived graphene coating can effectively enhance the corrosion efficiency of copper (Cu) in a seawater environment (0.5-0.6 M (???3.0-3.5%) sodium chloride). By applying a drop of acetone (???20 ??l cm-2) on Cu surfaces, rapid thermal annealing allows the facile and rapid synthesis of graphene films on Cu surfaces with a monolayer coverage of almost close to ???100%. Under optimal growth conditions, acetone-derived graphene is found to have a relatively high crystallinity, comparable to common graphene grown by chemical vapor deposition. The resulting graphene-coated Cu surface exhibits 37.5 times higher corrosion resistance as compared to that of mechanically polished Cu. Further, investigation on the role of graphene coating on Cu surfaces suggests that the outstanding corrosion inhibition efficiency (IE) of 97.4% is obtained by protecting the underlying Cu against the penetration of both dissolved oxygen and chlorine ions, thanks to the closely spaced atomic structure of the graphene sheets. The increase of graphene coating thickness results in the enhancement of the overall corrosion IE up to ???99%, which can be attributed to the effective blocking of the ionic diffusion process via grain boundaries. Overall, our results suggest that the acetone-derived graphene film can effectively serve as a corrosion-inhibiting coating in the seawater level and that it may have a promising role to play for potential offshore coating.close0

Combinatorial pharmacodynamics of polymyxin B and tigecycline against heteroresistant Acinetobacter baumannii

The prevalence of heteroresistant Acinetobacter baumannii is increasing. Infections due to these resistant pathogens pose a global treatment challenge. Here, the pharmacodynamic activities of polymyxin B (PMB) (2–20 mg/L) and tigecycline (0.15–4 mg/L) were evaluated as monotherapy and in combination using a 4 × 4 concentration array against two carbapenem-resistant and polymyxin-heteroresistant A. baumannii isolates. Time Kill Experiments was employed at starting inocula of 106 and 108 CFU/mL over 48 h. Clinically relevant combinations of PMB (2 mg/L) and tigecycline (0.90 mg/L) resulted in greater reductions in the bacterial population compared with polymyxin alone by 8 h (ATCC 19606, −6.38 vs. −3.43 log10 CFU/mL; FADDI AB115, −1.38 vs. 2.08 log10 CFU/mL). At 10× the clinically achievable concentration (PMB 20 mg/L in combination with tigecycline 0.90 mg/L), there was bactericidal activity against FADDI AB115 by 4 h that was sustained until 32 h, and against ATCC 19606 that was sustained for 48 h. These studies show that aggressive polymyxin-based dosing in combination with clinically achievable tigecycline concentrations results in early synergistic activity that is not sustained beyond 8 h, whereas combinations with higher tigecycline concentrations result in sustained bactericidal activity against both isolates at both inocula. These results indicate a need for optimised front-loaded polymyxin-based combination regimens that utilise high polymyxin doses at the onset of treatment to achieve good pharmacodynamic activity whilst minimising adverse events

Probing star formation across cosmic time with absorption line systems

We present an empirical connection between cold gas in galactic halos and star formation. Using a sample of more than 8,500 MgII absorbers from SDSS quasar spectra, we report the detection of a 15 sigma correlation between the rest equivalent width W0 of MgII absorbers and the associated OII luminosity, an estimator of star formation rate. This correlation has interesting implications: using only observable quantities we show that MgII absorbers trace a substantial fraction of the global OII luminosity density and recover the overall star formation history of the Universe derived from classical emission estimators up to z~2. We then show that the distribution function of MgII rest equivalent widths, dN/dW0 inherits both its shape and amplitude from the OII luminosity function Phi(L). These distributions can be naturally connected, without any free parameter. Our results imply a high covering factor of cold gas around star forming galaxies: C>0.5, favoring outflows as the mechanism responsible for MgII absorption. We then argue that intervening MgII absorbers and blue-shifted MgII absorption seen in the spectra of star forming galaxies are essentially the same systems. These results not only shed light on the nature of MgII absorbers but also provide us with a new probe of star formation, in absorption, i.e. in a way which does not suffer from dust extinction and with a redshift-independent sensitivity. As shown in this analysis, such a tool can be applied in a noise-dominated regime, i.e. using a dataset for which emission lines are not detected in individual objects. This is of particular interest for high redshift studies.Comment: 13 pages, 7 figures, submitted to MNRA

Impact of optical coherence tomography on diagnostic decision-making by UK community optometrists: a clinical vignette study.

PURPOSE: In recent years, there has been widespread investment in imaging technologies by community optometrists in the UK, most notably optical coherence tomography (OCT). The aim of the current study was to determine the value of OCT in the diagnosis of posterior segment diseases in a representative sample of community optometrists using a clinical vignette methodology. METHODS: A group of community optometrists (n = 50) initially completed a standardised training package on OCT interpretation followed by a computer-based assessment featuring 52 clinical vignettes, containing images of healthy (n = 8) or glaucomatous (n = 18) discs or healthy (n = 8) or diseased (n = 18) fundi. Each vignette featured either a single fundus/disc photographic image, or a combination of a fundus/disc image with the corresponding OCT scan. An expert panel confirmed that the fundus images presented alone and those in combination with OCT data were of a similar level of difficulty and that the cases were typical of those seen in primary care. For each case, the optometrist selected their diagnosis from a pull-down list and reported their confidence in their decision using a 10-point Likert scale. Pairwise comparisons of the fundus image alone and fundus image/OCT combination were made for both diagnostic performance and confidence. RESULTS: The mean percentage of correct diagnoses using fundus imaging alone was 62% (95% CI 59-64%) and for the combination of fundus image/OCT was 80% (95% CI 77-82%). The mean false negative rate with fundus alone was 27% reducing to 13% with the OCT combination. Median confidence scores for fundus imaging alone was 8.0 (IQR 7.0-8.0) and 8.3 (IQR 8.0-9.0) for the combination. Improvements in performance and confidence were statistically significant (p < 0.001). CONCLUSION: The results from this vignette study suggests that OCT improves optometrists' diagnostic performance compared to fundus observation alone. These initial results suggest that OCT provides valuable additional data that could augment case-finding for glaucoma and retinal disease; however, further research is needed to assess its diagnostic performance in a routine clinical practice setting

Polymyxin B in combination with doripenem against heteroresistant Acinetobacter baumannii : pharmacodynamics of new dosing strategies

Polymyxin B is being increasingly utilized as a last resort against resistant Gram-negative bacteria. We examined the pharmacodynamics of novel dosing strategies for polymyxin B combinations to maximize efficacy and minimize the emergence of resistance and drug exposure against Acinetobacter baumannii

A Kennicutt-Schmidt Law for Intervening Absorption Line Systems

We argue that most strong intervening metal absorption line systems, where the rest equivalent width of the MgII 2796A line is >0.5A, are interstellar material in, and outflowing from, star-forming disks. We show that a version of the Kennicutt-Schmidt law is readily obtained if the MgII equivalent widths are interpreted as kinematic broadening from absorbing gas in outflowing winds originating from star-forming galaxies. Taking a phenomenological approach and using a set of observational constraints available for star-forming galaxies, we are able to account for the density distribution of strong MgII absorbers over cosmic time. The association of intervening material with star-forming disks naturally explains the metallicity and dust content of strong MgII systems as well as their high HI column densities, and does not require the advection of metals from compact star-forming regions into the galaxy halos to account for the observations. We find that galaxies with a broad range of luminosities can give rise to absorption of a given rest-equivalent width, and discuss possible observational strategies to better quantify true galaxy-absorber associations and further test our model. We show that the redshift evolution in the density of absorbers closely tracks the star formation history of the universe and that strong intervening systems can be used to directly probe the physics of both bright and faint galaxies over a broad redshift range. By identifying strong intervening systems with galaxy disks and quantifying a version of the Kennicutt-Schmidt law that applies to them, a new probe of the interstellar medium is found which provides complementary information to that obtained through emission studies of galaxies. Implications of our results for galaxy feedback and enrichment of the intergalactic medium are discussed. [abridged]Comment: 23 pages, 15 figure

Relationship between subcellular localisation of Foscan® and caspase activation in photosensitised MCF-7 cells

The present study investigates the relationship between the subcellular localisation of Foscan® and intrinsic apoptotic pathway post Foscan®-based photodynamic therapy (PDT). With this purpose, mammary carcinoma MCF-7 cells were incubated with Foscan® for 3 or 24 h and then subjected to equitoxic light doses. Fluorescence microscopy revealed very good Foscan® co-localization to endoplasmic reticulum (ER) and Golgi apparatus after 3 h incubation with MCF-7 cells. Progressive increase in incubation time shows leakage of Foscan® from Golgi apparatus. Twenty-four hours incubation yielded a fluence-dependent enhanced induction of the ER-resident glucose-regulated protein 78 (Bip/GRP78), along with a weak mitochondrial damage, thus underscoring the ER as the main site of photodamage after prolonged incubation. Analysis of events implicated in apoptotic pathway after 24 h incubation demonstrated photodamage to Bcl-2 protein in total cellular extract, but not in the mitochondrial fraction. We further determined an increase in caspases-7 and -6 activation, which was strongly related to the expression of GRP78. The above findings demonstrate that Foscan® localisation in ER improves the photoactivation of the caspase-7 apoptotic pathway, which is poorly related to mitochondrial damage

Estimation of cancer incidence and mortality attributable to alcohol drinking in china

Background. Cancer constitutes a serious burden of disease worldwide and has become the second leading cause of death in China. Alcohol consumption is causally associated with the increased risk of certain cancers. Due to the current lack of data and the imperative need to guide policymakers on issues of cancer prevention and control, we aim to estimate the role of alcohol on the cancer burden in China in 2005. Methods. We calculated the proportion of cancers attributable to alcohol use to estimate the burden of alcohol-related cancer. The population attributable fraction was calculated based on the assumption of no alcohol drinking. Data on alcohol drinking prevalence were from two large-scale national surveys of representative samples of the Chinese population. Data on relative risk were obtained from meta-analyses and large-scale studies. Results. We found that a total of 78,881 cancer deaths were attributable to alcohol drinking in China in 2005, representing 4.40% of all cancers (6.69% in men, 0.42% in women). The corresponding figure for cancer incidence was 93,596 cases (3.63% of all cancer cases). Liver cancer was the main alcohol-related cancer, contributing more than 60% of alcohol-related cancers. Conclusions. Particular attention needs to be paid to the harm of alcohol as well as its potential benefits when making public health recommendations on alcohol drinking. \ua9 2010 Liang et al; licensee BioMed Central Ltd