121 research outputs found
Congruences of lines in , quadratic normality, and completely exceptional Monge-Amp\`ere equations
The existence is proved of two new families of locally Cohen-Macaulay sextic
threefolds in , which are not quadratically normal. These
threefolds arise naturally in the realm of first order congruences of lines as
focal loci and in the study of the completely exceptional Monge-Amp\`ere
equations. One of these families comes from a smooth congruence of multidegree
which is a smooth Fano fourfold of index two and genus 9.Comment: 16 page
The 35S U5 snRNP is generated from the activated spliceosome during In vitro splicing
Primary gene transcripts of eukaryotes contain introns, which are removed during processing by splicing machinery. Biochemical studies In vitro have identified a specific pathway in which introns are recognised and spliced out. This occurs by progressive formation of spliceosomal complexes designated as E, A, B, and C. The composition and structure of these spliceosomal conformations have been characterised in many detail. In contrast, transitions between the complexes and the intermediates of these reactions are currently less clear. We have previously isolated a novel 35S U5 snRNP from HeLa nuclear extracts. The protein composition of this particle differed from the canonical 20S U5 snRNPs but was remarkably similar to the activated B* spliceosomes. Based on this observation we have proposed a hypothesis that 35S U5 snRNPs represent a dissociation product of the spliceosome after both transesterification reactions are completed. Here we provide experimental evidence that 35S U5 snRNPs are generated from the activated B* spliceosomes during In vitro splicing
Grassmannians Gr(N-1,N+1), closed differential N-1 forms and N-dimensional integrable systems
Integrable flows on the Grassmannians Gr(N-1,N+1) are defined by the
requirement of closedness of the differential N-1 forms of rank
N-1 naturally associated with Gr(N-1,N+1). Gauge-invariant parts of these
flows, given by the systems of the N-1 quasi-linear differential equations,
describe coisotropic deformations of (N-1)-dimensional linear subspaces. For
the class of solutions which are Laurent polynomials in one variable these
systems coincide with N-dimensional integrable systems such as Liouville
equation (N=2), dispersionless Kadomtsev-Petviashvili equation (N=3),
dispersionless Toda equation (N=3), Plebanski second heavenly equation (N=4)
and others. Gauge invariant part of the forms provides us with
the compact form of the corresponding hierarchies. Dual quasi-linear systems
associated with the projectively dual Grassmannians Gr(2,N+1) are defined via
the requirement of the closedness of the dual forms . It
is shown that at N=3 the self-dual quasi-linear system, which is associated
with the harmonic (closed and co-closed) form , coincides with the
Maxwell equations for orthogonal electric and magnetic fields.Comment: 26 pages, references adde
Quantitative Proteome Profiling of C. burnetii under Tetracycline Stress Conditions
The recommended antibiotic regimen against Coxiella burnetii, the etiological agent of Q fever, is based on a semi-synthetic, second-generation tetracycline, doxycycline. Here, we report on the comparison of the proteomes of a C. burnetii reference strain either cultured under control conditions or under tetracycline stress conditions. Using the MS-driven combined fractional diagonal chromatography proteomics technique, out of the 531 proteins identified, 5 and 19 proteins were found significantly up- and down-regulated respectively, under tetracycline stress. Although the predicted cellular functions of these regulated proteins did not point to known tetracycline resistance mechanisms, our data clearly reveal the plasticity of the proteome of C. burnetii to battle tetracycline stress. Finally, we raise several plausible hypotheses that could further lead to more focused experiments on studying tetracycline resistance in C. burnetii and thus reduced treatment failures of Q fever
An improved map of the Galactic Faraday sky
We aim to summarize the current state of knowledge regarding Galactic Faraday
rotation in an all-sky map of the Galactic Faraday depth. For this we have
assembled the most extensive catalog of Faraday rotation data of compact
extragalactic polarized radio sources to date. In the map making procedure we
use a recently developed algorithm that reconstructs the map and the power
spectrum of a statistically isotropic and homogeneous field while taking into
account uncertainties in the noise statistics. This procedure is able to
identify some rotation angles that are offset by an integer multiple of pi. The
resulting map can be seen as an improved version of earlier such maps and is
made publicly available, along with a map of its uncertainty. For the angular
power spectrum we find a power law behavior with a power law index of -2.14 for
a Faraday sky where an overall variance profile as a function of Galactic
latitude has been removed, in agreement with earlier work. We show that this is
in accordance with a 3D Fourier power spectrum P(k) proportional to k^-2.14 of
the underlying field n_e times B_r under simplifying geometrical and
statistical assumptions.Comment: 16 pages, 11 figures. Update in one data catalog. All results are
available at http://www.mpa-garching.mpg.de/ift/faraday
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PEGylated systems in pharmaceutics
This review addresses the use of poly(ethylene glycol) (PEG) and PEG conjugation for the design of novel dosage forms and the modification of biomolecules. The peculiarities of PEGylated nanoparticles, liposomes, proteins, enzymes, and small drug and polyelectrolyte molecules and their influence on systemic drug delivery, including overcoming of various biological barriers and adhesion to mucosal tissues (mucoadhesion), are considered
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