823 research outputs found
Parcellation of Visual Cortex on high-resolution histological Brain Sections using Convolutional Neural Networks
Microscopic analysis of histological sections is considered the "gold
standard" to verify structural parcellations in the human brain. Its high
resolution allows the study of laminar and columnar patterns of cell
distributions, which build an important basis for the simulation of cortical
areas and networks. However, such cytoarchitectonic mapping is a semiautomatic,
time consuming process that does not scale with high throughput imaging. We
present an automatic approach for parcellating histological sections at 2um
resolution. It is based on a convolutional neural network that combines
topological information from probabilistic atlases with the texture features
learned from high-resolution cell-body stained images. The model is applied to
visual areas and trained on a sparse set of partial annotations. We show how
predictions are transferable to new brains and spatially consistent across
sections.Comment: Accepted for oral presentation at International Symposium of
Biomedical Imaging (ISBI) 201
Diattenuation of Brain Tissue and its Impact on 3D Polarized Light Imaging
3D-Polarized Light Imaging (3D-PLI) reconstructs nerve fibers in histological
brain sections by measuring their birefringence. This study investigates
another effect caused by the optical anisotropy of brain tissue -
diattenuation. Based on numerical and experimental studies and a complete
analytical description of the optical system, the diattenuation was determined
to be below 4 % in rat brain tissue. It was demonstrated that the diattenuation
effect has negligible impact on the fiber orientations derived by 3D-PLI. The
diattenuation signal, however, was found to highlight different anatomical
structures that cannot be distinguished with current imaging techniques, which
makes Diattenuation Imaging a promising extension to 3D-PLI.Comment: 32 pages, 15 figure
A Jones matrix formalism for simulating three-dimensional polarized light imaging of brain tissue
The neuroimaging technique three-dimensional polarized light imaging (3D-PLI)
provides a high-resolution reconstruction of nerve fibres in human post-mortem
brains. The orientations of the fibres are derived from birefringence
measurements of histological brain sections assuming that the nerve fibres -
consisting of an axon and a surrounding myelin sheath - are uniaxial
birefringent and that the measured optic axis is oriented in direction of the
nerve fibres (macroscopic model). Although experimental studies support this
assumption, the molecular structure of the myelin sheath suggests that the
birefringence of a nerve fibre can be described more precisely by multiple
optic axes oriented radially around the fibre axis (microscopic model). In this
paper, we compare the use of the macroscopic and the microscopic model for
simulating 3D-PLI by means of the Jones matrix formalism. The simulations show
that the macroscopic model ensures a reliable estimation of the fibre
orientations as long as the polarimeter does not resolve structures smaller
than the diameter of single fibres. In the case of fibre bundles, polarimeters
with even higher resolutions can be used without losing reliability. When
taking the myelin density into account, the derived fibre orientations are
considerably improved.Comment: 20 pages, 8 figure
ΠΠ΅ΡΠ΅Π΄Π°ΡΠ° Π΄Π°Π½Π½ΡΡ ΡΠ΅ΡΡΡ ΠΠΠΠ Π²Π΄ΠΎΠ»Ρ Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ΅ΠΊΡΠ° Π½Π° ΠΏΡΠΎΡΠΈΠ²ΠΎΠ»ΠΎΠ»ΠΎΠΆΠ½ΡΡ ΠΊΡΡΡΠ°Ρ
The process of data transmission by a network of unmanned aerial vehicles (UAVs) based on DPMR (Digital Private Mobile Radio) along an extended linear object is considered. A method of forming a network with the help of two UAVs moving in opposite directions with equal intervals between the devices within each of them is shown
ΠΡΠΎΠ±Π»Π΅ΠΌΠ° ΡΡΠΈΠ»ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ Π²ΡΠΎΡΠΈΡΠ½ΠΎΠΉ ΠΏΠ΅ΡΠ΅ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΠ»Π°ΡΡΠΈΠΊΠΎΠ²ΡΡ Π±ΡΡΡΠ»ΠΎΠΊ
ΠΡΠΎΠΈΡΡ
ΠΎΠ΄ΡΡΠΈΠ΅ Π³Π»ΠΎΠ±Π°Π»ΡΠ½ΡΠ΅ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ ΠΏΡΠ΅ΠΎΠ±ΡΠ°Π·ΠΎΠ²ΡΠ²Π°ΡΡ ΠΎΠ±ΡΡΠ½ΡΡ ΡΡΡΡΠ΅Π²ΡΡ ΡΠΊΠΎΠ½ΠΎΠΌΠΈΠΊΡ Π² Π²ΡΡΠΎΠΊΠΎΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ½ΡΡ, ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡΡΡ ΡΠ°ΡΠΈΠΎΠ½Π°Π»ΡΠ½ΠΎ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΡ ΠΈΠΌΠ΅ΡΡΠΈΠ΅ΡΡ ΡΠ΅ΡΡΡΡΡ ΠΈ ΠΏΡΠΈ ΡΡΠΎΠΌ Π½Π΅ Π·Π°Π³ΡΡΠ·Π½ΡΡΡ ΠΎΠΊΡΡΠΆΠ°ΡΡΡΡ Π½Π°Ρ ΡΡΠ΅Π΄Ρ. ΠΠ΅ΡΠ΅ΡΠ°Π±ΠΎΡΠΊΠ° ΠΠΠ’-Π±ΡΡΡΠ»ΠΎΠΊ ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ ΡΠ΅ΡΠΈΡΡ ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΡΡΠΈΠ»ΠΈΠ·Π°ΡΠΈΠΈ ΠΏΠ»Π°ΡΡΠΈΠΊΠΎΠ²ΠΎΠ³ΠΎ ΠΌΡΡΠΎΡΠ° ΠΈ ΠΌΠΎΠΆΠ΅Ρ ΡΡΠ°ΡΡ ΠΏΡΠΈΠ±ΡΠ»ΡΠ½ΡΠΌ Π±ΠΈΠ·Π½Π΅ΡΠΎΠΌ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ, ΡΡΠΎ ΡΡΡΡΠ΅, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΠΎΠ΅ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΠΏΠ΅ΡΠ΅ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΠ»Π°ΡΡΠΈΠΊΠΎΠ²ΡΡ
Π±ΡΡΡΠ»ΠΎΠΊ, ΠΌΠΎΠΆΠ΅Ρ Π±ΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΎ Π΄Π»Ρ ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΡ Π²ΠΎΡΡΡΠ΅Π±ΠΎΠ²Π°Π½Π½ΠΎΠΉ ΠΏΡΠΎΠ΄ΡΠΊΡΠΈΠΈ.The ongoing global changes transform the conventional raw material economy into a high-tech one, allowing rational use of available resources and at the same time to not polluting the environment around us. Recycling of PET bottles will solve the problem of recycling plastic trash and can become a profitable business. The results of the research showed that secondary raw material, obtained during the processing of plastic bottles can be used for the production of the demanded products
Contour Proposal Networks for Biomedical Instance Segmentation
We present a conceptually simple framework for object instance segmentation
called Contour Proposal Network (CPN), which detects possibly overlapping
objects in an image while simultaneously fitting closed object contours using
an interpretable, fixed-sized representation based on Fourier Descriptors. The
CPN can incorporate state of the art object detection architectures as backbone
networks into a single-stage instance segmentation model that can be trained
end-to-end. We construct CPN models with different backbone networks, and apply
them to instance segmentation of cells in datasets from different modalities.
In our experiments, we show CPNs that outperform U-Nets and Mask R-CNNs in
instance segmentation accuracy, and present variants with execution times
suitable for real-time applications. The trained models generalize well across
different domains of cell types. Since the main assumption of the framework are
closed object contours, it is applicable to a wide range of detection problems
also outside the biomedical domain. An implementation of the model architecture
in PyTorch is freely available
Contrastive Representation Learning for Whole Brain Cytoarchitectonic Mapping in Histological Human Brain Sections
Cytoarchitectonic maps provide microstructural reference parcellations of the
brain, describing its organization in terms of the spatial arrangement of
neuronal cell bodies as measured from histological tissue sections. Recent work
provided the first automatic segmentations of cytoarchitectonic areas in the
visual system using Convolutional Neural Networks. We aim to extend this
approach to become applicable to a wider range of brain areas, envisioning a
solution for mapping the complete human brain. Inspired by recent success in
image classification, we propose a contrastive learning objective for encoding
microscopic image patches into robust microstructural features, which are
efficient for cytoarchitectonic area classification. We show that a model
pre-trained using this learning task outperforms a model trained from scratch,
as well as a model pre-trained on a recently proposed auxiliary task. We
perform cluster analysis in the feature space to show that the learned
representations form anatomically meaningful groups.Comment: Accepted to ISBI 202
3D Polarized Light Imaging Portrayed: Visualization of Fiber Architecture Derived from 3D-PLI
3D polarized light imaging (3D-PLI) is a neuroimaging technique that has recently opened up new avenues to study the complex architecture of nerve fibers in postmortem brains at microscopic scales. In a specific voxel-based analysis, each voxel is assigned a single 3D fiber orientation vector. This leads to comprehensive 3D vector fields. In order to inspect and analyze such high-resolution fiber orientation vector field, also in combination with complementary microscopy measurements, appropriate visualization techniques are essential to overcome several challenges, such as the massive data sizes, the large amount of both unique and redundant information at different scales, or the occlusion issues of inner structures by outer layers. Here, we introduce a comprehensive software tool that is able to visualize all information of a typical 3D-PLI dataset in an adequate and sophisticated manner. This includes the visualization of (i) anatomic structural and fiber architectonic data in one representation, (ii) a large-scale fiber orientation vector field, and (iii) a clustered version of the field. Alignment of a 3D-PLI dataset to an appropriate brain atlas provides expert-based delineation, segmentation, and, ultimately, visualization of selected anatomical structures. By means of these techniques, a detailed analysis of the complex fiber architecture in 3D is feasible
Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΠ° Π±Π΅ΡΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ³ΠΎ ΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠ°
Π¦Π΅Π»ΡΡ Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ° Π±Π΅ΡΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠ° ΠΈ Π°Π½Π°Π»ΠΈΠ· Π΅Π³ΠΎ ΡΠ²ΠΎΠΉΡΡΠ². Π ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΠΈΠ·ΡΡΠ΅Π½ΠΈΡ Π±ΡΠ»ΠΈ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ ΠΏΡΠΈΠ½ΡΠΈΠΏΡ ΡΠ»Π΅ΠΊΡΡΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠΈΠΈ ΠΈ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ ΡΡΠ΄ ΡΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΎΠ² ΠΏΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΠ»Π΅ΠΊΡΡΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠ²ΠΎΠΉΡΡΠ². Π ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π±ΡΠ»ΠΈ ΠΈΠ·ΡΡΠ΅Π½Ρ Π²ΠΎΠΏΡΠΎΡΡ ΠΈ ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΡΠ²ΡΠ·Π°Π½Π½ΡΠ΅ Ρ ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΠ΅ΠΉ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π±Π΅ΡΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΊΠ°ΡΠ΄ΠΈΠΎΠ³ΡΠ°ΡΠ°, ΡΠ°ΠΊΠΆΠ΅ Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ ΠΎΡΠ΅Π½ΠΊΠΈ Π΅Π³ΠΎ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ.The aim of this work is to develop a non-contact electrocardiograph and analysis of its properties. During the study, the basic principles of electrocardiography were considered and a number of experiments were conducted to study the electrocardiographic properties. As a result of the study, questions and problems related to the implementation of the development of a non-contact electrocardiograph were studied, and estimates of its characteristics were also obtained
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