274 research outputs found
Tetracycline Treatment Retards the Onset and Slows the Progression of Diabetes in Human Amylin/Islet Amyloid Polypeptide Transgenic Mice
Ultra-strong Adhesion of Graphene Membranes
As mechanical structures enter the nanoscale regime, the influence of van der
Waals forces increases. Graphene is attractive for nanomechanical systems
because its Young's modulus and strength are both intrinsically high, but the
mechanical behavior of graphene is also strongly influenced by the van der
Waals force. For example, this force clamps graphene samples to substrates, and
also holds together the individual graphene sheets in multilayer samples. Here
we use a pressurized blister test to directly measure the adhesion energy of
graphene sheets with a silicon oxide substrate. We find an adhesion energy of
0.45 \pm 0.02 J/m2 for monolayer graphene and 0.31 \pm 0.03 J/m2 for samples
containing 2-5 graphene sheets. These values are larger than the adhesion
energies measured in typical micromechanical structures and are comparable to
solid/liquid adhesion energies. We attribute this to the extreme flexibility of
graphene, which allows it to conform to the topography of even the smoothest
substrates, thus making its interaction with the substrate more liquid-like
than solid-like.Comment: to appear in Nature Nanotechnolog
11β-HSD1 inhibition does not affect murine tumour angiogenesis but may exert a selective effect on tumour growth by modulating inflammation and fibrosis
Mathematical Properties of a New Levin-Type Sequence Transformation Introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. I. Algebraic Theory
\v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la [J. Math. Phys. \textbf{44}, 962
- 968 (2003)] introduced in connection with the summation of the divergent
perturbation expansion of the hydrogen atom in an external magnetic field a new
sequence transformation which uses as input data not only the elements of a
sequence of partial sums, but also explicit estimates
for the truncation errors. The explicit
incorporation of the information contained in the truncation error estimates
makes this and related transformations potentially much more powerful than for
instance Pad\'{e} approximants. Special cases of the new transformation are
sequence transformations introduced by Levin [Int. J. Comput. Math. B
\textbf{3}, 371 - 388 (1973)] and Weniger [Comput. Phys. Rep. \textbf{10}, 189
- 371 (1989), Sections 7 -9; Numer. Algor. \textbf{3}, 477 - 486 (1992)] and
also a variant of Richardson extrapolation [Phil. Trans. Roy. Soc. London A
\textbf{226}, 299 - 349 (1927)]. The algebraic theory of these transformations
- explicit expressions, recurrence formulas, explicit expressions in the case
of special remainder estimates, and asymptotic order estimates satisfied by
rational approximants to power series - is formulated in terms of hitherto
unknown mathematical properties of the new transformation introduced by
\v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. This leads to a considerable
formal simplification and unification.Comment: 41 + ii pages, LaTeX2e, 0 figures. Submitted to Journal of
Mathematical Physic
Mid-Infrared Imaging of Candidate Vega-Like Systems
We have conducted deep mid-infrared imaging of a relatively nearby sample of
candidate Vega-like stars using the OSCIR instrument on the CTIO 4-meter and
Keck II 10-meter telescopes. Our discovery of a spatially-resolved disk around
HR 4796A has already been reported (Jayawardhana et al. 1998). Here we present
imaging observations of the other members of the sample, including the
discovery that only the primary in the HD 35187 binary system appears to harbor
a substantial circumstellar disk and the possible detection of extended disk
emission around 49 Ceti. We derive global properties of the dust disks, place
constraints on their sizes, and discuss several interesting cases in detail.
Although our targets are believed to be main sequence stars, we note that
several have large infrared excesses compared to prototype Vega-like systems,
and may therefore be somewhat younger. The disk size constraints we derive, in
many cases, imply emission from relatively large ( 10m) particles
at mid-infrared wavelengths.Comment: 15 pages and 2 PostScript figures, accepted for publication in The
Astronomical Journa
Recommended from our members
A pilot randomised controlled trial using prophylactic dressings to minimise sacral pressure injuries in high risk hospitalised patients
This pilot randomised controlled trial examined the effect of prophylactic dressings to minimise sacral pressure injuries in high-risk hospitalised patients and assessed feasibility criteria to inform a larger study. Eighty patients were recruited at admission points (the Emergency Department and Surgical Care Unit) or directly from participating wards in the general medical surgical setting following assessment of high risk for sacral pressure injury. Participants were randomised into either the routine care or routine care and silicone foam border dressing group. Outcome assessment comprised digital photographs of each participant’s sacrum every 72 hours for evaluation by a blind-to-intervention assessor. Sixty-seven participants had at least one sacral photograph taken and assessed by a blind-to-intervention assessor. Three participants were assessed as having a Stage I pressure injury. While the use of photography was effective, feasibility criteria identified challenges related to bias, blinding, weight assessment, preparation of nursing staff and sample size estimation
Hegel, Adorno and the origins of immanent criticism
‘Immanent criticism' has been discussed by philosophers of quite different persuasions, working in separate areas and in different traditions of philosophy. Almost all of them agree on roughly the same story about its origins: It is that Hegel invented immanent criticism, that Marx later developed it, and that the various members of the Frankfurt School, particularly Adorno, refined it in various ways, and that they are all paradigmatic practitioners of immanent criticism. I call this the Continuity Thesis. There are four different claims that interest me. (i) Hegel is the originator of immanent criticism. (ii) Hegel's dialectical method is that of immanent criticism. (iii) Adorno practises immanent criticism and endorses the term as a description of his practice. (iv) Adorno's dialectical method is fundamentally Hegelian. In this article, I offer an account of immanent criticism, on the basis of which, I evaluate these four claims and argue that the Continuity Thesis should be rejected
Comparative mapping in the Poaceae family reveals translocations in the complex polyploid genome of sugarcane
How long do nosocomial pathogens persist on inanimate surfaces? A systematic review
BACKGROUND: Inanimate surfaces have often been described as the source for outbreaks of nosocomial infections. The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces. METHODS: The literature was systematically reviewed in MedLine without language restrictions. In addition, cited articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included. RESULTS: Most gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae, however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days. Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV type 1 and 2, have been shown to persist from only a few hours up to 7 days. CONCLUSION: The most common nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of transmission if no regular preventive surface disinfection is performed
Genetic dissection of fruit quality traits in the octoploid cultivated strawberry highlights the role of homoeo-QTL in their control
Fruit quality traits are major breeding targets in the Rosaceae. Several of the major Rosaceae species are current or ancient polyploids. To dissect the inheritance of fruit quality traits in polyploid fleshy fruit species, we used a cultivated strawberry segregating population comprising a 213 full-sibling F1 progeny from a cross between the variety ‘Capitola’ and the genotype ‘CF1116’. We previously developed the most comprehensive strawberry linkage map, which displays seven homoeology groups (HG), including each four homoeology linkage groups (Genetics 179:2045–2060, 2008). The map was used to identify quantitative trait loci (QTL) for 19 fruit traits related to fruit development, texture, colour, anthocyanin, sugar and organic acid contents. Analyses were carried out over two or three successive years on field-grown plants. QTL were detected for all the analysed traits. Because strawberry is an octopolyploid species, QTL controlling a given trait and located at orthologous positions on different homoeologous linkage groups within one HG are considered as homoeo-QTL. We found that, for various traits, about one-fourth of QTL were putative homoeo-QTL and were localised on two linkage groups. Several homoeo-QTL could be detected the same year, suggesting that several copies of the gene underlying the QTL are functional. The detection of some other homoeo-QTL was year-dependent. Therefore, changes in allelic expression could take place in response to environmental changes. We believe that, in strawberry as in other polyploid fruit species, the mechanisms unravelled in the present study may play a crucial role in the variations of fruit quality
- …