19,053 research outputs found
The Brauer-Manin obstruction on algebraic stacks
For algebraic stacks over a number field, we define their Brauer-Manin
pairings, Brauer-Manin sets, and extend the descent theory of
Colliot-Th\'el\`ene and Sansuc. By extending Sansuc's exact sequence, we show
the torsionness of Brauer groups of stacks that are locally quotients of
varieties by connected groups. With mild assumptions, for stacks that are
locally quotients or Deligne-Mumford, we show that the Brauer-Manin obstruction
coincides with some other cohomological obstructions such as obstructions given
by torsors under connected groups or abelian gerbes, generalizing Harari's
original results. For Brauer-Manin sets on these stacks, we show the properties
such as descent along a torsor, product preservation are still correct. These
results extend classical theories of those on varieties.Comment: 16 pages, revised some proofs (git: 20220302/60acc33
Peptide-Mediated Liposomal Drug Delivery System Targeting Tumor Blood Vessels in Anticancer Therapy
Solid tumors are known to recruit new blood vessels to support their growth. Therefore, unique molecules expressed on tumor endothelial cells can function as targets for the antiangiogenic therapy of cancer. Current efforts are focusing on developing therapeutic agents capable of specifically targeting cancer cells and tumor-associated microenvironments including tumor blood vessels. These therapies hold the promise of high efficacy and low toxicity. One recognized strategy for improving the therapeutic effectiveness of conventional chemotherapeutics is to encapsulate anticancer drugs into targeting liposomes that bind to the cell surface receptors expressed on tumor-associated endothelial cells. These anti-angiogenic drug delivery systems could be used to target both tumor blood vessels as well as the tumor cells, themselves. This article reviews the mechanisms and advantages of various present and potential methods using peptide-conjugated liposomes to specifically destroy tumor blood vessels in anticancer therapy
Modeling the pulse signal by wave-shape function and analyzing by synchrosqueezing transform
We apply the recently developed adaptive non-harmonic model based on the
wave-shape function, as well as the time-frequency analysis tool called
synchrosqueezing transform (SST) to model and analyze oscillatory physiological
signals. To demonstrate how the model and algorithm work, we apply them to
study the pulse wave signal. By extracting features called the spectral pulse
signature, {and} based on functional regression, we characterize the
hemodynamics from the radial pulse wave signals recorded by the
sphygmomanometer. Analysis results suggest the potential of the proposed signal
processing approach to extract health-related hemodynamics features
5,5′-Bis[(2,2,2-trifluoroethoxy)methyl]-2,2′-bipyridine
The complete molecule of the title compound, C16H14F6N2O2, is generated by crystallographic inversion symmetry, which results in two short intramolecular C—H⋯N hydrogen-bond contacts per molecule. In the crystal, aromatic π–π stacking [centroid–centroid distance = 3.457 (2) Å] and weak C—H⋯π interactions occur. A short H⋯H [2.32 (3) Å] contact is present
Loss of vesicular dopamine release precedes tauopathy in degenerative dopaminergic neurons in a Drosophila model expressing human tau.
While a number of genome-wide association studies have identified microtubule-associated protein tau as a strong risk factor for Parkinson's disease (PD), little is known about the mechanism through which human tau can predispose an individual to this disease. Here, we demonstrate that expression of human wild-type tau is sufficient to disrupt the survival of dopaminergic neurons in a Drosophila model. Tau triggers a synaptic pathology visualized by vesicular monoamine transporter-pHGFP that precedes both the age-dependent formation of tau-containing neurofibrillary tangle-like pathology and the progressive loss of DA neurons, thereby recapitulating the pathological hallmarks of PD. Flies overexpressing tau also exhibit progressive impairments of both motor and learning behaviors. Surprisingly, contrary to common belief that hyperphosphorylated tau could aggravate toxicity, DA neuron degeneration is alleviated by expressing the modified, hyperphosphorylated tau(E14). Together, these results show that impairment of VMAT-containing synaptic vesicle, released to synapses before overt tauopathy may be the underlying mechanism of tau-associated PD and suggest that correction or prevention of this deficit may be appropriate targets for early therapeutic intervention
Legendrian mean curvature flow in -Einstein Sasakian manifolds
Recently, there are a great deal of work done which connects the Legendrian
isotopic problem with contact invariants. The isotopic problem of Legendre
curve in a contact 3-manifold was studies via the Legendrian curve shortening
flow which was introduced and studied by K. Smoczyk. On the other hand, in the
SYZ Conjecture, one can model a special Lagrangian singularity locally as the
special Lagrangian cones in C^{3}. This can be characterized by its link which
is a minimal Legendrian surface in the 5-sphere. Then in these points of view,
in this paper we will focus on the existence of the long-time solution and
asymptotic convergence along the Legendrian mean curvature flow in higher
dimensional {\eta}-Einstein Sasakian (2n+1)-manifolds under the suitable
stability condition due to the Thomas-Yau conjecture.Comment: arXiv admin note: text overlap with arXiv:0906.5527 by other author
Subjective and objective watermark detection using a novel approach: Bar-coded watermarking
Many digital watermarking algorithms are proposed in the literature. Broadly these watermarking algorithms can be classified into two main categories. The first category of algorithms uses a pseudo random Gaussian sequence (PRGS) watermark whereas the second category of algorithms uses a binary logo as a watermark. The main advantage of PRGS based watermarking scheme is its ability to detect the presence of watermark without manual intervention. However the main drawback is calculating reliable threshold value. In the similar manner the main advantage of binary logo watermark is that there is no need to calculate threshold value but requires manual intervention to detect the presence of watermark. The advantage and disadvantage of either approach is quite clear hence it would be a good idea to design a watermarking scheme which inherits the advantages from both these approaches. In this paper we present one such approach which is termed as bar-code watermarking. The proposed scheme offers objective as well as subjective detection. A PRGS sequence watermark is represented as a bar-code on a binary logo and embedded in the host image. Watermark detection can be either done subjectively or objectively
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