Composition of Ices in Low-Mass Extrasolar Planets

We study the formation conditions of icy planetesimals in protoplanetary disks in order to determine the composition of ices in small and cold extrasolar planets. Assuming that ices are formed from hydrates, clathrates, and pure condensates, we calculate their mass fractions with respect to the total quantity of ices included in planetesimals, for a grid of disk models. We find that the composition of ices weakly depends on the adopted disk thermodynamic conditions, and is rather influenced by the initial composition of the gas phase. The use of a plausible range of molecular abundance ratios and the variation of the relative elemental carbon over oxygen ratio in the gas phase of protoplanetary disks, allow us to apply our model to a wide range of planetary systems. Our results can thus be used to constrain the icy/volatile phase composition of cold planets evidenced by microlensing surveys, hypothetical ocean-planets and carbon planets, which could be detected by Corot or Kepler.Comment: Accepted for publication in The Astrophysical Journa

Magnetospheric considerations for solar system ice state

The current lattice configuration of the water ice on the surfaces of the inner satellites of Jupiter and Saturn is likely shaped by many factors. But laboratory experiments have found that energetic proton irradiation can cause a transition in the structure of pure water ice from crystalline to amorphous. It is not known to what extent this process is competitive with other processes in solar system contexts. For example, surface regions that are rich in water ice may be too warm for this effect to be important, even if the energetic proton bombardment rate is very high. In this paper, we make predictions, based on particle flux levels and other considerations, about where in the magnetospheres of Jupiter and Saturn the ∼MeV proton irradiation mechanism should be most relevant. Our results support the conclusions of Hansen and McCord (2004), who related relative level of radiation on the three outer Galilean satellites to the amorphous ice content within the top 1 mm of surface. We argue here that if magnetospheric effects are considered more carefully, the correlation is even more compelling. Crystalline ice is by far the dominant ice state detected on the inner Saturnian satellites and, as we show here, the flux of bombarding energetic protons onto these bodies is much smaller than at the inner Jovian satellites. Therefore, the ice on the Saturnian satellites also corroborates the correlation

Surface mannosylation of dispersion polymerisation derived nanoparticles by copper mediated click chemistry

The synthesis of spherical polymeric nanoparticles containing alkyne surface functionalities for post poly- merisation glycosylation is described. The nanoparticles were obtained by a polymerisation induced self- assembly (PISA) inspired methodology in dispersed media by Cu(0) mediated polymerisation. A water soluble poly(ethylene glycol methacrylate-stat-propargyl methacrylate), poly(PEGMA18-stat-PgMA5), macroinitiator was first synthesised and chain extended with 2-hydroxypropyl methacrylate (HPMA) in water using a copper wire catalyst. It was found that irrespective of the macroinitiator to HPMA ratio and the reaction time the desired spherical morphologies (<100 nm) were obtained while the absence other morphologies suggest a deviation from the classical PISA process due to chain termination in the nano- particle’s core. The obtained nanoparticles contained alkyne functionalities in the shell, which were suc- cessfully reacted by copper mediated click chemistry with fluoresceine azide and mannosides with hydro- phobic and hydrophilic spacers of different lengths. The obtained mannosylated nanoparticles displayed no significant cytotoxicity against human alveolar basal epithelial adenocarcinomic (A549) cells at any dose <0.5 mg mL−1. Preliminary binding studies confirm the ability of the mannosylated nanoparticles to bind to human lectin dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN). The methodology reported here is a convenient route to well-defined spherical and shell- functionalisable nanoparticles to create libraries of bio-active nanomaterials

Evaluation of a commercially developed semiautomated PCR-surface-enhanced Raman scattering assay for diagnosis of invasive fungal disease

Nonculture-based tests are gaining popularity in the diagnosis of invasive fungal disease (IFD), but PCR is excluded from disease-defining criteria because of limited standardization and a lack of commercial assays. Commercial PCR assays may have a standardized methodology while providing quality assurance. The detection of PCR products by a surface-enhanced Raman scattering (SERS) assay potentially provides superior analytical sensitivity and multiplexing capacity compared to that of real-time PCR. Using this approach, the RenDx Fungiplex assay was developed to detect Candida and Aspergillus. Analytical and clinical evaluations of the assay were undertaken using extraction methods according to European Aspergillus PCR Initiative (EAPCRI) recommendations. A total of 195 previously extracted samples (133 plasma, 49 serum, and 13 whole blood) from 112 patients (29 with proven/probable IFD) were tested. The 95% limit of detection of Candida and Aspergillus was 200 copies per reaction, with an overall reproducibility of 92.1% for detecting 20 input copies per PCR, and 89.8% for the nucleic acid extraction–PCR-SERS process for detecting fungal burdens of <20 genome equivalents per sample. A clinical evaluation showed that assay positivity significantly correlated with IFD (P < 0.0001). The sensitivity of the assay was 82.8% and was similar for both Candida (80.0%) and Aspergillus (85.7%). The specificity was 87.5% and was increased (97.5%) by using a multiple (≥2 samples) PCR-positive threshold. In summary, the RenDx Fungiplex assay is a PCR-SERS assay for diagnosing IFD and demonstrates promising clinical performance on a variety of samples. This was a retrospective clinical evaluation, and performance is likely to be enhanced through a prospective analysis of clinical validity and by determining clinical utility

Character and spatial distribution of OH/H<SUB>2</SUB>O on the surface of the moon seen by M<SUP>3</SUP> on Chandrayaan-1

The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration

Human papillomavirus prevalence among indigenous and non-indigenous Australian women prior to a national HPV vaccination program

<p>Abstract</p> <p>Background</p> <p>Indigenous women in Australia have a disproportionate burden of cervical cancer despite a national cervical screening program. Prior to introduction of a national human papilloma virus (HPV) vaccination program, we determined HPV genotype prevalence by Indigenous status and residence in remote areas.</p> <p>Methods</p> <p>We recruited women aged 17 to 40 years presenting to community-based primary health services for routine Pap screening across Australia. A liquid-based cytology (LBC) cervical specimen was tested for HPV DNA using the AMPLICOR HPV-DNA test and a PGMY09/11-based HPV consensus PCR; positive specimens were typed by reverse hybridization. We calculated age-adjusted prevalence by weighting to relevant population data, and determined predictors of HPV-DNA positivity by age, Indigenous status and area of residence using logistic regression.</p> <p>Results</p> <p>Of 2152 women (655 Indigenous), prevalence of the high-risk HPV genotypes was similar for Indigenous and non-Indigenous women (HPV 16 was 9.4% and 10.5%, respectively; HPV 18 was 4.1% and 3.8%, respectively), and did not differ by age group. In younger age groups, the prevalence of other genotypes also did not differ, but in those aged 31 to 40 years, HPV prevalence was higher for Indigenous women (35% versus 22.5%; <it>P </it>< 0.001), specifically HPV clades α5 (OR = 2.1, 95% CI 1.1 to 4.3) and α7, excluding type 18 (OR 1.9, 95% CI 1.1 to 3.3). In multivariate analysis, detection of any HPV genotype was strongly associated with smoking and Pap-test abnormalities, with both risk factors more common among Indigenous women.</p> <p>Conclusion</p> <p>Although we found no difference in the prevalence of HPV16/18 among Australian women by Indigenous status or, for Indigenous women, residence in remote regions, differences were found in the prevalence of risk factors and some other HPV genotypes. This reinforces the importance of cervical screening as a complement to vaccination for all women, and the value of baseline data on HPV genotype prevalence by Indigenous status and residence for the monitoring of vaccine impact.</p

Density functional theory based screening of ternary alkali-transition metal borohydrides: A computational material design project

The dissociation of molecules, even the most simple hydrogen molecule, cannot be described accurately within density functional theory because none of the currently available functionals accounts for strong on-site correlation. This problem led to a discussion of properties that the local Kohn-Sham potential has to satisfy in order to correctly describe strongly correlated systems. We derive an analytic expression for the nontrivial form of the Kohn-Sham potential in between the two fragments for the dissociation of a single bond. We show that the numerical calculations for a one-dimensional two-electron model system indeed approach and reach this limit. It is shown that the functional form of the potential is universal, i.e., independent of the details of the two fragments.We acknowledge funding by the Spanish MEC (Grant No. FIS2007-65702-C02-01), “Grupos Consolidados UPV/EHU del Gobierno Vasco” (Grant No. IT-319-07), and the European Community through e-I3 ETSF project (Grant Agreement No. 211956).Peer reviewe