Search results for "interference"

Aerial Spectrum Surveying: Radio Map Estimation with Autonomous UAVs

2020

Radio maps are emerging as a popular means to endow next-generation wireless communications with situational awareness. In particular, radio maps are expected to play a central role in unmanned aerial vehicle (UAV) communications since they can be used to determine interference or channel gain at a spatial location where a UAV has not been before. Existing methods for radio map estimation utilize measurements collected by sensors whose locations cannot be controlled. In contrast, this paper proposes a scheme in which a UAV collects measurements along a trajectory. This trajectory is designed to obtain accurate estimates of the target radio map in a short time operation. The route planning a…

Arbitrary Phase Access for Stable Fiber Interferometers

2021

Well-controlled yet practical systems that give access to interference effects are critical for established and new functionalities in ultrafast signal processing, quantum photonics, optical coherence characterization, etc. Optical fiber systems constitute a central platform for such technologies. However, harnessing optical interference in a versatile and stable manner remains technologically costly and challenging. Here, degrees of freedom native to optical fibers, i.e., polarization and frequency, are used to demonstrate an easily deployable technique for the retrieval and stabilization of the relative phase in fiber interferometric systems. The scheme gives access (without intricate dev…

Valoda: nozīme un forma, 3: Teorija un metodoloģija latviešu valodniecībā

2013

The mitotic kinase Aurora-A promotes distant metastases by inducing epithelial-to-mesenchymal transition in ERα+ breast cancer cells

2013

In this study, we demonstrate that constitutive activation of Raf-1 oncogenic signaling induces stabilization and accumulation of Aurora-A mitotic kinase that ultimately drives the transition from an epithelial to a highly invasive mesenchymal phenotype in estrogen receptor α-positive (ERα(+)) breast cancer cells. The transition from an epithelial- to a mesenchymal-like phenotype was characterized by reduced expression of ERα, HER-2/Neu overexpression and loss of CD24 surface receptor (CD24(-/low)). Importantly, expression of key epithelial-to-mesenchymal transition (EMT) markers and upregulation of the stemness gene SOX2 was linked to acquisition of stem cell-like properties such as the ab…

Multifunctional Cationic PeptoStars as siRNA Carrier: Influence of Architecture and Histidine Modification on Knockdown Potential.

2019

RNA interference provides enormous potential for the treatment of several diseases, including cancer. Nevertheless, successful therapies based on siRNA require overcoming various challenges, such as poor pharmacokinetic characteristics of the small RNA molecule and inefficient cytosolic accumulation. In this respect, the development of functional siRNA carrier systems is a major task in biomedical research. To provide such a desired system, the synthesis of 3-arm and 6-arm PeptoStars is aimed for. The different branched polypept(o)idic architectures share a stealth-like polysarcosine corona for efficient shielding and a multifunctional polylysine core, which can be independently varied in s…

proTRAC - a software for probabilistic piRNA cluster detection, visualization and analysis

2012

Abstract Background Throughout the metazoan lineage, typically gonadal expressed Piwi proteins and their guiding piRNAs (~26-32nt in length) form a protective mechanism of RNA interference directed against the propagation of transposable elements (TEs). Most piRNAs are generated from genomic piRNA clusters. Annotation of experimentally obtained piRNAs from small RNA/cDNA-libraries and detection of genomic piRNA clusters are crucial for a thorough understanding of the still enigmatic piRNA pathway, especially in an evolutionary context. Currently, detection of piRNA clusters relies on bioinformatics rather than detection and sequencing of primary piRNA cluster transcripts and the stringency …

Dye selection for live cell imaging of intact siRNA

2011

Abstract Investigations into the fate of small interfering RNA (siRNA) after transfection may unravel new ways to improve RNA interference (RNAi) efficiency. Because intracellular degradation of RNA may prevent reliable observation of fluorescence-labeled siRNA, new tools for fluorescence microscopy are warranted to cover the considerable duration of the RNAi effect. Here, the characterization and application of new fluorescence resonance energy transfer (FRET) dye pairs for sensing the integrity of duplex siRNA is reported, which allows an assessment of the degradation status of an siRNA cell population by live cell imaging. A panel of high-yield fluorescent dyes has been investigated for …

Enhancing Gene Knockdown Efficiencies by Comparing siRNA-Loaded Cationic Nanogel Particles of Different Sizes

2015

lt;pgt;In order to silence the expression levels of pathogenic genes, small interfering RNA (siRNA) requires a nano-sized carrier for its safe and stable delivery into cells. In this research highlight, we focus on well-defined cationic nanohydrogel particles developed in our group for such purposes. To investigate the nanogels’ mechanism for enhanced knockdown efficiencies, we recently synthesized two sets of particles with similar material composition and siRNA-loading characteristics, but – according to the manufacturing process – of different sizes. Within this study, 100-nm-sized nanogel particles loaded with siRNA accumulated inside the lysosomes already after 4 h and could not induce…

A novel antiviral approach.

2012

Viral infections are often the etiological agents of severe acute and chronic human diseases. Their peculiar biology usually leads to the need of design specific therapies for each virus, and the eradication of the viruses and the healing of the patients very often are not reached also after decades of theoretical and applied researches. HIV is a classical example of how the efforts of the researchers may be disappointed in eradicating a virus infection in an infected patient. Here I present a hypothesis for a new antiviral approach that may be suitable for the treatment of HIV infected patients. The same approach, with opportune modifications, may be also applied as healing strategy for a …

Efficient selection of silenced primary cells by flow cytometry

2007

Background: RNA interference has emerged as a new and potent tool to knockdown the expression of target genes and to investigate their functions. For short time experiments with mammalian cell lines, RNA interference is typically induced by transfecting small interfering RNAs (siRNAs). Primary cells constitute important experimental systems in many studies because of their similarity to their in vivo counterparts; however, transfection of these cells has been found to be difficult. As a consequence, RNA interference of primary cells may result in mixed phenotypes because of the simultaneous presence in the same preparation of transfected and nontransfected cells. This may be particularly in…