1,504 research outputs found
Subkutane Dirofilariasis: Infektion mit Dirofilaria repens.
A female patient resident in Germany is described, who had developed dirofilariasis presenting as a hard subcutaneous nodule at the glabella. Dirofilaria repens was isolated after surgical removal of the skin lesion. She was treated with diethylcarbamazine (Hetrazan) for 4 weeks. Exposures related to infection with Dirofilaria repens are discussed
CO diffusion and desorption kinetics in CO ices
Diffusion of species in icy dust grain mantles is a fundamental process that
shapes the chemistry of interstellar regions; yet measurements of diffusion in
interstellar ice analogs are scarce. Here we present measurements of CO
diffusion into CO ice at low temperatures (T=11--23~K) using CO
longitudinal optical (LO) phonon modes to monitor the level of mixing of
initially layered ices. We model the diffusion kinetics using Fick's second law
and find the temperature dependent diffusion coefficients are well fit by an
Arrhenius equation giving a diffusion barrier of 300 40 K. The low
barrier along with the diffusion kinetics through isotopically labeled layers
suggest that CO diffuses through CO along pore surfaces rather than through
bulk diffusion. In complementary experiments, we measure the desorption energy
of CO from CO ices deposited at 11-50 K by temperature-programmed
desorption (TPD) and find that the desorption barrier ranges from 1240 90
K to 1410 70 K depending on the CO deposition temperature and
resultant ice porosity. The measured CO-CO desorption barriers demonstrate
that CO binds equally well to CO and HO ices when both are compact. The
CO-CO diffusion-desorption barrier ratio ranges from 0.21-0.24 dependent on
the binding environment during diffusion. The diffusion-desorption ratio is
consistent with the above hypothesis that the observed diffusion is a surface
process and adds to previous experimental evidence on diffusion in water ice
that suggests surface diffusion is important to the mobility of molecules
within interstellar ices
A Survey of CH3CN and HC3N in Protoplanetary Disks
The organic content of protoplanetary disks sets the initial compositions of
planets and comets, thereby influencing subsequent chemistry that is possible
in nascent planetary systems. We present observations of the complex
nitrile-bearing species CH3CN and HC3N towards the disks around the T Tauri
stars AS 209, IM Lup, LkCa 15, and V4046 Sgr as well as the Herbig Ae stars MWC
480 and HD 163296. HC3N is detected towards all disks except IM Lup, and CH3CN
is detected towards V4046 Sgr, MWC 480, and HD 163296. Rotational temperatures
derived for disks with multiple detected lines range from 29-73K, indicating
emission from the temperate molecular layer of the disk. V4046 Sgr and MWC 480
radial abundance profiles are constrained using a parametric model; the
gas-phase CH3CN and HC3N abundances with respect to HCN are a few to tens of
percent in the inner 100 AU of the disk, signifying a rich nitrile chemistry at
planet- and comet-forming disk radii. We find consistent relative abundances of
CH3CN, HC3N, and HCN between our disk sample, protostellar envelopes, and solar
system comets; this is suggestive of a robust nitrile chemistry with similar
outcomes under a wide range of physical conditions
Genetic diversity, infection prevalence, and possible transmission routes of Bartonella spp. in vampire bats
Bartonella spp. are globally distributed bacteria that cause endocarditis in humans and domestic animals. Recent work has suggested bats as zoonotic reservoirs of some human Bartonella infections; however, the ecological and spatiotemporal patterns of infection in bats remain largely unknown. Here we studied the genetic diversity, prevalence of infection across seasons and years, individual risk factors, and possible transmission routes of Bartonella in populations of common vampire bats (Desmodus rotundus) in Peru and Belize, for which high infection prevalence has previously been reported. Phylogenetic analysis of the gltA gene for a subset of PCR-positive blood samples revealed sequences that were related to Bartonella described from vampire bats from Mexico, other Neotropical bat species, and streblid bat flies. Sequences associated with vampire bats clustered significantly by country but commonly spanned Central and South America, implying limited spatial structure. Stable and nonzero Bartonella prevalence between years supported endemic transmission in all sites. The odds of Bartonella infection for individual bats was unrelated to the intensity of bat flies ectoparasitism, but nearly all infected bats were infested, which precluded conclusive assessment of support for vector-borne transmission. While metagenomic sequencing found no strong evidence of Bartonella DNA in pooled bat saliva and fecal samples, we detected PCR positivity in individual saliva and feces, suggesting the potential for bacterial transmission through both direct contact (i.e., biting) and environmental (i.e., fecal) exposures. Further investigating the relative contributions of direct contact, environmental, and vector-borne transmission for bat Bartonella is an important next step to predict infection dynamics within bats and the risks of human and livestock exposures
A colimit decomposition for homotopy algebras in Cat
Badzioch showed that in the category of simplicial sets each homotopy algebra
of a Lawvere theory is weakly equivalent to a strict algebra. In seeking to
extend this result to other contexts Rosicky observed a key point to be that
each homotopy colimit in simplicial sets admits a decomposition into a homotopy
sifted colimit of finite coproducts, and asked the author whether a similar
decomposition holds in the 2-category of categories Cat. Our purpose in the
present paper is to show that this is the case.Comment: Some notation changed; small amount of exposition added in intr
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