scholarly journals Impact of Cell Density and Collagen Concentration on the Electromagnetic Properties of Dermal Equivalents in the Terahertz Band

2018 ◽  
Vol 8 (4) ◽  
pp. 381-389 ◽  
Author(s):  
Rui Zhang ◽  
Ke Yang ◽  
Qammer H. Abbasi ◽  
Najah Abed AbuAli ◽  
Akram Alomainy
Keyword(s):  
Cell Density ◽  
Electromagnetic Properties ◽  
Collagen Concentration ◽  
Terahertz Band ◽  
Dermal Equivalents

scholarly journals Modelling Multilayer Communication Channel in Terahertz Band for Medical Applications

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Essraa Hesham Mahmoud ◽  
Mohammed S. Gadelrab ◽  
Khaled ElSayed ◽  
Abdel Rahman Sallam
Keyword(s):  
Human Body ◽  
Communication Channel ◽  
Channel Model ◽  
Path Loss ◽  
Electromagnetic Properties ◽  
Medical Field ◽  
Terahertz Band ◽  
Body Tissues ◽  
Terahertz Communication ◽  
Combined Channel

In this work we present a multi-layer channel model for terahertz communication that incorporates both layers of human body tissues and textile layers. Many research works tackled communication channel modelling in human body alone while some other research focused on textile characterization/modelling alone. There is a real gap in connecting these different models. To investigate this, a multi-layer channel model for terahertz communication is developed, this model assumes external textile layer stacked over layers of human body tissues. The electromagnetic properties of the different layers are extracted from previous works that used time domain spectroscopy (TDS) in the terahertz band to characterize each of the considered layers. The model is implemented as a flexible MATLAB/Octave program that enables the simulation of layers with either fixed or random depths. This paper aims to pave the way to connecting patients’ in-body nano-nodes with off-body (on-cloth) nano-nodes by building such a combined channel model. This helps in many applications especially in the medical field. For example, having connected nano-nodes can help in diagnosing diseases, monitoring health by sending information to the external environment, treatment (e.g., increasing or decreasing a certain dose depending on the monitoring), etc. The obtained results show how the THz signal can be affected when it propagates through heterogeneous mediums (i.e., human body tissues and textile). Various types of path-loss has been calculated for this purpose and verified by comparison with results from previous research on separate models of human body and textile.

scholarly journals All-dielectric chiral coding metasurface based on spin-decoupling in terahertz band

Nanophotonics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 1347-1355
Author(s):  
Chenglong Zheng ◽  
Jie Li ◽  
Guocui Wang ◽  
Jitao Li ◽  
Silei Wang ◽  
...  
Keyword(s):  
The Other ◽  
Electromagnetic Properties ◽  
Dual Function ◽  
Vortex Beam ◽  
Cd Spectra ◽  
Superposition State ◽  
Polarization Imaging ◽  
Chiral Metamaterials ◽  
Terahertz Band ◽  
Novel Approach

Abstract Metamaterials can achieve superior electromagnetic properties over natural materials by adjusting the structure of the meta-atoms. Chiral metamaterials have been widely used in circular dichroism (CD) spectra, polarization imaging, and optical sensing. Here we propose a kind of all-silicon coding metasurfaces to achieve the function similar to chirality by spin decoupling. One of the two circularly polarized (CP) channels is scattered randomly, and the desired function is only designed in the other opposite CP channel. Three kinds of coding metasurfaces are designed to verify the reliability of such approach: one simultaneously possessing dual function of transmitting directly and scattering randomly, one capable of generating the superposition state of vortex beam, and the other generating the Bessel vortex beam, respectively. And some experimental verifications are carried out. This scheme is simpler and more versatile than previous schemes which require elaborate designed structure of the meta-atoms. Our novel approach provides a new option for implementing tunable chirality.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Increassed parietal cell density in patients with perfurated duodenal ulcer: Comparison with non-complicated duodenal ulcer patients

2001 ◽  
Vol 120 (5) ◽  
pp. A250-A250
Author(s):  
A BARBOSA ◽  
C MENDES ◽  
L COELHO ◽  
C RODRIGUES ◽  
M MACHADO ◽  
...  
Keyword(s):  
Duodenal Ulcer ◽  
Cell Density ◽  
Parietal Cell

Rapeseed Oil and Sunflower Oil Diets Enhance Platelet In Vitro Aggregation and Thromboxane Production in Healthy Men when Compared with Milk Fat or Habitual Diets

1992 ◽  
Vol 67 (03) ◽  
pp. 352-356 ◽  
Author(s):  
Marja Mutanen ◽  
Riitta Freese ◽  
Liisa M Valsta ◽  
Irma Ahola ◽  
Antti Ahlström
Keyword(s):  
Sunflower Oil ◽  
Milk Fat ◽  
Rapeseed Oil ◽  
Controlled Trial ◽  
Collagen Concentration ◽  
Aggregation Pattern ◽  
Thromboxane Production ◽  
Low Erucic Acid ◽  
Platelet Thromboxane

SummaryIn this highly controlled trial, 26 normolipidemic men (average age 28 years, range 18 to 60) were fed a baseline diet high in milk fat (MF) (fat 36% of energy, saturates 19%, monounsaturates 11%, polyunsaturates 4%), followed by a diet high in sunflower oil (SO) (fat 38% of energy, saturates 13%, monounsaturates 10%, polyunsaturates 13%) and another diet high in low erucic-acid rapeseed oil (RO) (fat 38% of energy, saturates 12%, monounsaturates 16%, polyunsaturates 8%). All diets were mixed natural diets with the same cholesterol contents. The baseline milk fat diet was given for 14 days and the oil diets for 24 days in a blind cross-over design. The platelet in vitro aggregation (slope %/min) induced by 1, 2 and 3 pM ADP and collagen (25 pg/ml PRP) was highly significantly (p <0.001) increased after both oil diets when compared with the results from the milk fat diet. The aggregation pattern determined by threshold collagen concentration confirmed increased collagen sensitivity of the platelets after the rapeseed oil diet (p <0.001). The enhancement of platelet aggregation was associated with increased in vitro platelet thromboxane production after the oil diets vs. the milk fat diet (p <0.05 after the sunflower oil diet and p <0.001 after the rapeseed oil diet).

Comparative Study of Size, Total Protein, Fibrinogen and 5-HT Content of Human and Canine Platelet Density Subpopulations

1986 ◽  
Vol 56 (03) ◽  
pp. 288-292 ◽  
Author(s):  
Diego Mezzano ◽  
Eduardo Aranda ◽  
Arnaldo Foradori
Keyword(s):  
Comparative Study ◽  
Protein Content ◽  
Cell Density ◽  
Total Protein ◽  
Unit Volume ◽  
Low Density ◽  
Dense Bodies ◽  
Artifactual Changes ◽  
Platelet Release ◽  
The Difference

SummaryThe size, total protein, fibrinogen and 5-HT content were evaluated in density subpopulations of human and canine platelets fractionated in linear arabinogalactan gradients. The methodology was assessed to ascertain that platelet separation was by density and to discard artifactual changes and platelet release during the procedure. EDTA or PGEi increased the size of human PRP-platelets, but not of dog platelets. In humans, high density (HD) platelets were 1.26 times larger and contained 1.88 times more fibrinogen, 2.23 times more 5-HT and 1.37 times more protein than low density (LD) platelets; in dogs, these density cohorts did not differ in protein content, but LD platelets were 1.29 times larger and had 1.33 times more fibrinogen and 5-HT than HD platelets. These findings suggest that cell density is mostly dependent on the protein content per unit volume of platelets (and not on dense bodies). The differences in fibrinogen and 5-HT content between HD and LD cohorts in humans and dogs may be related to platelet age. The difference in volume between HD and LD platelets in dogs is of uncertain interpretation.

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