ABSTRACT We present results of an optical search conducted as part of the SH0ES project (Supernovae and H0 for the Equation of State of dark energy) for Cepheid variable stars using the Hubble Space ...Telescope (HST) in 19 hosts of Type Ia supernovae (SNe Ia) and the maser-host galaxy NGC 4258. The targets include nine newly imaged SN Ia hosts using a novel strategy based on a long-pass filter that minimizes the number of HST orbits required to detect and accurately determine Cepheid properties. We carried out a homogeneous reduction and analysis of all observations, including new universal variability searches in all SN Ia hosts, which yielded a total of 2200 variables with well-defined selection criteria, the largest such sample identified outside the Local Group. These objects are used in a companion paper to determine the local value of H0 with a total uncertainty of 2.4%.
The emulsifying and stabilization efficiency of polybutadiene-b-poly(ethylene oxide) and poly(ter butylstyrene)–poly(ethylene oxide) diblock copolymers is examined in non-aqueous emulsions. These ...emulsions are formed by a dispersion of polyethylene glycol mixed with a cationic surfactant acting as a biocide, in a continuous phase of a thermoplastic elastomer (SEBS) dissolved in methylcyclohexane. Emulsions with controlled droplet size and excellent stability could be obtained, which by solvent evaporation lead to elastomeric films containing droplets of confined disinfecting liquids.
Recently, an Ile93Met substitution has been identified in the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) gene in a single German PD family with autosomal dominant inheritance. To determine ...whether mutations in the UCHL1 gene are causative for Parkinson's disease (PD) a detailed mutation analysis was performed in a large sample of German sporadic and familial PD patients. We found no disease-causing mutation in the coding region of the UCHL1 gene. Direct sequencing revealed six intronic polymorphisms in the UCHL1 gene. Analysis of an S18Y polymorphism in exon 3 of the UCHL1 gene in sporadic PD patients and controls showed carriers of allele 2 (tyrosine) significantly less frequent in patients with a reduced risk of 0.57 (CI = 0.36-0.88; p = 0.012, p(c) = 0.047, chi2 = 6.31). Our study shows that sequence variations in the coding region of UCHL1 are a rare event. A protective effect of a certain UCHL1 variant in the pathogenesis of sporadic PD is suggested, underlining the relevance of UCHL1 in neurodegeneration.
Decreases in brain N-acetylaspartate are associated with neuronal loss or dysfunction. We report a longitudinal study in which changes in the N-acetylaspartate to creatine resonance intensity ratio ...measured by brain proton magnetic resonance spectroscopy were used to follow the progression of brain pathology in 7 patients with multiple sclerosis over an 18-month period. Four of the patients had a history of recurrent relapses and 3 had a secondary progressive course. All had clinical and magnetic resonance imaging evidence of persistent neurological abnormalities. At 6-month intervals proton magnetic resonance spectra were obtained and the N-acetylaspartate-creatine ratio was determined for each patient. The volumes of hyperintense signal from lesions on conventional magnetic resonance images and the Kurtzke Expanded Disability Status Scale scores were determined concurrently. At the onset of the study, the N-acetylaspartate-creatine ratio was significantly (p < 0.05) lower in the central brain volumes from the patients than in 13 normal control subjects. At 12 and 18 months of follow-up, the ratio had decreased further in all patients (p < 0.05), consistent with progressive accumulation of neuronal damage. In contrast to magnetic resonance spectra data, changes in lesion volume on magnetic resonance images or disability status did not reach significance over this period. Subgroup analysis showed that changes (increases or decreases) in the N-acetylaspartate-creatine ratio between consecutive 6-month examinations correlated significantly (r = -0.74, p < 0.005) with changes in lesion volume on magnetic resonance images in patients with a history of relapses.
ABSTRACT We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement ...comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample of reliable SNe Ia having a Cepheid-calibrated distance to a total of 19; these in turn leverage the magnitude-redshift relation based on ∼300 SNe Ia at z < 0.15. All 19 hosts as well as the megamaser system NGC 4258 have been observed with WFC3 in the optical and NIR, thus nullifying cross-instrument zeropoint errors in the relative distance estimates from Cepheids. Other noteworthy improvements include a 33% reduction in the systematic uncertainty in the maser distance to NGC 4258, a larger sample of Cepheids in the Large Magellanic Cloud (LMC), a more robust distance to the LMC based on late-type detached eclipsing binaries (DEBs), HST observations of Cepheids in M31, and new HST-based trigonometric parallaxes for Milky Way (MW) Cepheids. We consider four geometric distance calibrations of Cepheids: (i) megamasers in NGC 4258, (ii) 8 DEBs in the LMC, (iii) 15 MW Cepheids with parallaxes measured with HST/FGS, HST/WFC3 spatial scanning and/or Hipparcos, and (iv) 2 DEBs in M31. The Hubble constant from each is 72.25 2.51, 72.04 2.67, 76.18 2.37, and 74.50 3.27 km s−1 Mpc−1, respectively. Our best estimate of H0 = 73.24 1.74 km s−1 Mpc−1 combines the anchors NGC 4258, MW, and LMC, yielding a 2.4% determination (all quoted uncertainties include fully propagated statistical and systematic components). This value is 3.4 higher than 66.93 0.62 km s−1 Mpc−1 predicted by ΛCDM with 3 neutrino flavors having a mass of 0.06 eV and the new Planck data, but the discrepancy reduces to 2.1 relative to the prediction of 69.3 0.7 km s−1 Mpc−1 based on the comparably precise combination of WMAP+ACT+SPT+BAO observations, suggesting that systematic uncertainties in CMB radiation measurements may play a role in the tension. If we take the conflict between Planck high-redshift measurements and our local determination of H0 at face value, one plausible explanation could involve an additional source of dark radiation in the early universe in the range of ΔNeff 0.4-1. We anticipate further significant improvements in H0 from upcoming parallax measurements of long-period MW Cepheids.
In the past decade, several rapidly-evolving transients have been discovered whose timescales and luminosities are not easily explained by traditional supernovae (SN) models. The sample size of these ...objects has remained small due, at least in part, to the challenge of detecting short timescale transients with traditional survey cadences. Here we present the results from a search within the Pan-STARRS1 Medium Deep Survey (PS1-MDS) for rapidly-evolving and luminous transients. We identify 10 new transients with a time above half-maximum of less than 12 days and -16.5 > M > -20 mag. This increases the number of known events in this region of SN phase space by roughly a factor of three. The median redshift of the PS1-MDS sample is z=0.275 and they all exploded in star forming galaxies. In general, the transients possess faster rise than decline timescale and blue colors at maximum light (g - r < -0.2). Best fit blackbodies reveal photospheric temperatures/radii that expand/cool with time and explosion spectra taken near maximum light are dominated by a blue continuum, consistent with a hot, optically thick, ejecta. We find it difficult to reconcile the short timescale, high peak luminosity (L > 10^43 erg/s), and lack of UV line blanketing observed in many of these transients with an explosion powered mainly by the radioactive decay of Ni-56. Rather, we find that many are consistent with either (1) cooling envelope emission from the explosion of a star with a low-mass extended envelope which ejected very little (<0.03 M_sun) radioactive material, or (2) a shock breakout within a dense, optically thick, wind surrounding the progenitor star. After calculating the detection efficiency for objects with rapid timescales in the PS1-MDS we find a volumetric rate of 4800 - 8000 events/yr/Gpc^3 (4-7% of the core-collapse SN rate at z=0.2).
The paper concerns the preparation and characterization of hydrogel microparticles based on exopolysaccharide (Gellan, Xanthan) unsaturated derivatives and respectively on cyclodextrin as well as ...their application for some hydrosoluble and liposoluble drugs inclusion. In the first step the polysaccharide and cyclodextrin unsaturated esters (maleate, acrylate) were synthesized and their hydrogel forming capacity was tested using a grafting‐crosslinking free‐radical reaction with N‐isopropyl acrylamide (NIPAm), at room temperature. For a better control of the crosslinking degree N,N' methylene‐bis‐acrylamide (BIS), replaced by cyclodextrin tri‐acrylate (A‐CD) in a few experiments, was used. The microparticles were obtained by using the method in w/o emulsion, in which the dispersed aqueous phase is the reaction mixture and the oil phase is hexane. The particles containing polysaccharide esters showed an average diameter around 100 µm when crosslinking was achieved with BIS. They were smaller than those crosslinked with A‐CD, which are in the range of 200‐300 µm; the particles based on Xanthan maleate were smaller than Gellan maleate based ones. Even much smaller particles (2‐2.5 µm in diameter) were obtained by starting from A‐CD grafted‐crosslinked systems. The synthesized microparticles are able to include chloramphenicol, as well as progesterone; the drug is slowly released according to diffusion controlled kinetics. The application of these microparticles in emergency ophthalmic treatments is possible as a result of their thermal sensitivity; they can collapse and release the drug instantly when placed in contact with the human eye, at 37 °C.
The genetic etiology of human lipid quantitative traits is not fully elucidated, and interactions between variants may play a role. We performed a gene-centric interaction study for four different ...lipid traits: low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and triglycerides (TG).
Our analysis consisted of a discovery phase using a merged dataset of five different cohorts (
= 12,853 to
= 16,849 depending on lipid phenotype) and a replication phase with ten independent cohorts totaling up to 36,938 additional samples. Filters are often applied before interaction testing to correct for the burden of testing all pairwise interactions. We used two different filters: 1. A filter that tested only single nucleotide polymorphisms (SNPs) with a main effect of
< 0.001 in a previous association study. 2. A filter that only tested interactions identified by Biofilter 2.0. Pairwise models that reached an interaction significance level of
< 0.001 in the discovery dataset were tested for replication. We identified thirteen SNP-SNP models that were significant in more than one replication cohort after accounting for multiple testing.
These results may reveal novel insights into the genetic etiology of lipid levels. Furthermore, we developed a pipeline to perform a computationally efficient interaction analysis with multi-cohort replication.
Poly(ethylene oxide)‐block‐poly(methylidene malonate 2.1.2) block copolymer (PEO‐b‐PMM 2.1.2) bearing an allyl moiety at the poly(ethylene oxide) chain end was synthesized by sequential anionic ...polymerization of ethylene oxide (EO) and methylidene malonate 2.1.2 (MM 2.1.2). This allyl functional group was subsequently modified by reaction with thiol‐bearing functional groups to generate carboxyl and amino functionalized biodegradable block copolymers. These end‐group reactions, performed in good yields both in organic media and in aqueous micellar solutions, lead to functionalized PEO‐b‐PMM 2.1.2 copolymers which are of interest for cell targeting purposes.
Synthetic route to α‐allyl functionalized PEO‐b‐PMM 2.1.2 copolymers.
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