1,434 research outputs found
Towards clinical translation of raman spectroscopy for tumor cell identification
In the modern world, cancer is one of the leading causes of death, and its early diagnostics remains one of the big challenges. Since cancer starts as a malfunction on the cellular level, the diagnostic techniques have to deal with single cells. Detection of circulating tumor cells (CTCs), which are present in the patient's blood, holds promise for the future theranostic applications, as CTCs represent the actual state of the primary tumor. Raman spectroscopy is a label-free technique capable of non-destructive and chemically-specific characterization of individual cells. In contrast to marker-based methods, the CTCs detected by Raman can be reused for more specific single-cells biochemical analysis methods. This thesis focuses on technological developments for Raman-based CTC identification, and encompasses the whole chain of involved methods and processes, including instrumentation and microfluidic cell handling, automation of spectra acquisition and storage, and chemometric data analysis. It starts with a design of custom application-specific instruments that we used to evaluate and optimize different experimental parameters. A major part is software development for automated acquisition and organized storage of spectral data in a database. With the automated measurement systems and the database in place, we were able to collect about 40.000 Raman spectra of more than 15 incubated cancer cell lines, healthy donor leukocytes, as well as samples originating from clinical patients. Additionally, the thesis gives an overview of data analysis methods and provides an insight into the underlying trends of the dataset. Although the cell identification models could not reliably differentiate between individual cancer cell lines, they were able to recognize tumor cells among healthy leukocytes with prediction accuracy of more than 95%. This work demonstrated an increase in the throughput of Raman-based CTC detection, and provides a basis for its clinical translation
Quantum repeater via entangled phase modulated multimode coherent states
We present a scheme of quantum repeater that uses entangled multimode
coherent states which are obtained by electro-optic modulation of symmetric and
antisymmetric Schr\"odinger cat states. In this method subcarrier modes of the
phase modulated states generated by the remote parties are sent to a symmetric
beam splitter at the central node. The entangled coherent states are heraldedly
prepared by photon counting measurements at the output channels of the beam
splitter. We study how the effects of decoherence in the quantum channel affect
statistics of photocounts and corresponding fidelity. We show how the proposed
scheme can be useful for extending range of quantum key distribution with sub
carrier wave encoding by exploiting quantum teleportation with the generated
entanglement.Comment: 14 pages, 8 figure
Theoretical analysis of quantum key distribution systems when integrated with a DWDM optical transport network
A theoretical research and numerical simulation of the noise influence caused
by spontaneous Raman scattering, four-wave mixing, and linear channel crosstalk
on the performance of QKD systems was conducted. Three types of QKD systems
were considered: coherent one-way (COW) QKD protocol, subcarrier-wave (SCW) QKD
system, and continuous-variable (CV) QKD integrated with classical DWDM
channels. We calculate the secure key generation rate for the systems mentioned
addressing different channel allocation schemes (i.e., configurations). A
uniform DWDM grid is considered with quantum channel located in C-band and
O-band (at 1310 nm) of a telecommunication window. The systems' performance is
analyzed in terms of the maximal achievable distance values. Configurations for
the further analysis and investigation are chosen optimally, i.e., their
maximal achievable distances are the best
Tungstate and Carbonate Ions Sorption Using Anion Exchangers AV-17-8 and Purolite A400
The current paper shows the results of tungstate and carbonate ion sorption using strongly basic anion exchangers AV-17-8 and Purolite A400. It has been established that anion exchanger AV-17-8 in the chloride form with parameters of 168 g of tungstate ion and 157 g of carbonate ion per 1 kg of anion exchanger has the maximum capacity for the tungstate and carbonate ions
Data transmission in long-range dielectric-loaded surface plasmon polariton waveguides
In this paper we report successful transmission of 10 Gbit/s on-off-keying
(OOK) modulated signal through the LR-DLSPPWs with almost negligible
degradation of the data flow consistenc
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High-bit rate ultra-compact light routing with mode-selective on-chip nanoantennas
Optical nanoantennas provide a promising pathway toward advanced manipulation of light waves, such as directional scattering, polarization conversion, and fluorescence enhancement. Although these functionalities were mainly studied for nanoantennas in free space or on homogeneous substrates, their integration with optical waveguides offers an important “wired” connection to other functional optical components. Taking advantage of the nanoantenna’s versatility and unrivaled compactness, their imprinting onto optical waveguides would enable a marked enhancement of design freedom and integration density for optical on-chip devices. Several examples of this concept have been demonstrated recently. However, the important question of whether nanoantennas can fulfill functionalities for high-bit rate signal transmission without degradation, which is the core purpose of many integrated optical applications, has not yet been experimentally investigated. We introduce and investigate directional, polarization-selective, and mode-selective on-chip nanoantennas integrated with a silicon rib waveguide. We demonstrate that these nanoantennas can separate optical signals with different polarizations by coupling the different polarizations of light vertically to different waveguide modes propagating into opposite directions. As the central result of this work, we show the suitability of this concept for the control of optical signals with ASK (amplitude-shift keying) NRZ (nonreturn to zero) modulation [10 Gigabit/s (Gb/s)] without significant bit error rate impairments. Our results demonstrate that waveguide-integrated nanoantennas have the potential to be used as ultra-compact polarization-demultiplexing on-chip devices for high–bit rate telecommunication applications
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