MASS MULTIFRACTAL CHARACTERIZATION OF BLOOD VESSEL SYSTEMS

Fractals ◽  
1996 ◽  
Vol 04 (02) ◽  
pp. 133-138 ◽  
Author(s):  
F. JESTCZEMSKI ◽  
M. SERNETZ
Keyword(s):  
Probability Distribution ◽  
Blood Vessel ◽  
Total Mass ◽  
Generalized Dimensions ◽  
Multifractal Property ◽  
The Masses

The blood vessel system as measured on kidney1 and placenta arteries2,3 is known to be a non-homogeneous fractal with a distribution of local dimensions. We interpret this distribution as a mass multifractal property and we have therefore examined the average of the masses Mi(r) and their qth moments within boxes of increasing size r. The centers i of the boxes are randomly distributed on the vessels. The generalized dimensions Dq are introduced by taking the average of (Mi(r)/M0)q-1 over the centers i, according to the probability distribution Mi(r)/M0 (M0: total mass of the cluster). Thus, we have determined Dq by calculating <(Mi(r)/M0)q-1>< centers i> ∝ (r/L)(q-1) Dq (L: diameter of the cluster).

Development and Biomechanical Characterization of a Novel Bilayer Vascular Graft

2010 ◽  
Author(s):  
Krishna Madhavan ◽  
Walter Bonani ◽  
Craig Lanning ◽  
Wei Tan
Keyword(s):  
Blood Vessel ◽  
Vascular Graft ◽  
Bypass Surgery ◽  
Small Diameter ◽  
Native Artery ◽  
Vessel Lumen ◽  
Unmet Demand ◽  
Tissue Engineered Blood Vessels ◽  
Synthetic Grafts

Vascular grafts are currently used to treat cardiovascular diseases such as arthrosclerosis by bypass surgery and as vascular access in hemodialysis [1]. There are a number of types of grafts including autologous vessels (such saphenous vein), synthetic grafts (such as expanded polytetrafluoroethylene) and tissue engineered blood vessels. Currently synthetic grafts are most commonly used as blood vessel replacements and there are a number of problems associated with them. One main impediment is that these grafts are not suitable for small-diameter (less than 6mm) vessel replacement [1, 2], due to high occlusion rates. The major concern over the other alternatives such as autologous vessels and tissue engineered products is their availability. Thus, new approaches to constructing biomimetic small-diameter blood vessel equivalents, that are immediately available, may address the unmet demand in this area. Therefore, we have designed a novel bilayer vascular construct which is made up of a nanofibrous intimal-equivalent as thromboresistant vessel lumen and a mimetic extracellular matrix (ECM) as medial-equivalent for smooth muscle cells (SMC) from native artery to invade and remodel the ECM.

scholarly journals On the question of the treatment of uterine blood tumors

2020 ◽  
Vol 11 (4) ◽  
pp. 403-417
Author(s):  
Gr. N. Egorov
Keyword(s):  
Blood Vessel ◽  
Whole Blood ◽  
Total Mass ◽  
Lymphatic System ◽  
Blood Clot ◽  
Abdominal Cavity ◽  
The Body ◽  
Long Time ◽  
Life Threatening

The abdominal cavity is, in essence, an appendage of the lymphatic system, therefore, it cannot represent a completely foreign container for the blood poured out here. Indeed, the observations of Virchow, Wintrich and others show that whole blood can remain in this cavity for a long time (several days) without undergoing clotting (Pashutin). In view of this fact, it is natural to expect, as is confirmed by experiments, that most of the blood that has entered the abdominal cavity has time to be absorbed before it begins to coagulate. If a part of it, which failed to be absorbed in time, undergoes clotting, then this does not represent any particular disturbances in the overall economy of blood, the blood clot is completely absorbed after preliminary disintegration (fat). In this sense, hemorrhage into the abdominal cavity is not life-threatening, since the blood does not disappear for the body, but soon again, almost entirely, enters the total mass of the blood vessel.

scholarly journals On the equivalence of various definitions of mixed poisson processes

2019 ◽  
Vol 69 (2) ◽  
pp. 453-468
Author(s):  
Demetrios P. Lyberopoulos ◽  
Nikolaos D. Macheras ◽  
Spyridon M. Tzaninis
Keyword(s):  
Probability Distribution ◽  
Poisson Process ◽  
Random Variable ◽  
Poisson Processes ◽  
Counting Processes ◽  
Mixing Parameter ◽  
Mixed Poisson Process ◽  
Probability Spaces ◽  
The One

Abstract Under mild assumptions the equivalence of the mixed Poisson process with mixing parameter a real-valued random variable to the one with mixing probability distribution as well as to the mixed Poisson process in the sense of Huang is obtained, and a characterization of each one of the above mixed Poisson processes in terms of disintegrations is provided. Moreover, some examples of “canonical” probability spaces admitting counting processes satisfying the equivalence of all above statements are given. Finally, it is shown that our assumptions for the characterization of mixed Poisson processes in terms of disintegrations cannot be omitted.

scholarly journals From Planetary Nebula nuclei to white dwarfs: The impact of evolutionary envelope masses

1997 ◽  
Vol 180 ◽  
pp. 389-389 ◽  
Author(s):  
T. Blöcker ◽  
F. Herwig ◽  
T. Driebe ◽  
H. Bramkamp ◽  
D. Schönberner
Keyword(s):  
Planetary Nebula ◽  
Total Mass ◽  
White Dwarfs ◽  
Stellar Mass ◽  
Asymptotic Giant Branch ◽  
The Masses ◽  
The Impact

It is well known that the evolution of white dwarfs (WDs) depends sensitively on the question whether they have “thin” or “thick” envelopes of H and He (see Wood 1995). Standard evolutionary caluclations (e.g. Paczynksi 1971) show that at the tip of the Asymptotic Giant Branch the envelope masses are tightly correlated with the mass of the hydrogen exhausted core (≈ total mass). Accordingly, the masses of hydrogen, MH, and helium, MHe, on top of the degenerate C/O interiors decrease by orders of magnitudes with increasing stellar mass. In contrast, many applications of WD calculations consider only single values of qH,He = log(MH,He/M∗) asuming either “thick” or “thin” envelopes.

scholarly journals Spectrophotometric characterization of the Philae landing site and surroundings with the Rosetta/OSIRIS cameras

2020 ◽  
Vol 498 (1) ◽  
pp. 1221-1238
Author(s):  
Hong Van Hoang ◽  
S Fornasier ◽  
E Quirico ◽  
P H Hasselmann ◽  
M A Barucci ◽  
...  
Keyword(s):  
Total Mass ◽  
Morphological Changes ◽  
Landing Site ◽  
Spectral Slope ◽  
Water Ice ◽  
Total Mass Loss ◽  
Before And After ◽  
Comet 67P ◽  
Cometary Activity

ABSTRACT We investigate Abydos, the final landing site of the Philae lander after its eventful landing from the Rosetta spacecraft on comet 67P/Churyumov–Gerasimenko on 2014 November 12. Over 1000 OSIRIS-level 3B images were analysed, which cover the 2014 August–2016 September timeframe, with spatial resolution ranging from 7.6 m pixel−1 to approximately 0.06 m pixel−1. We found that the Abydos site is as dark as the global 67P nucleus and spectrally red, with an average albedo of 6.5 per cent at 649 nm and a spectral slope value of about 17 per cent/(100 nm) at 50° phase angle. Similar to the whole nucleus, the Abydos site also shows phase reddening but with lower coefficients than other regions of the comet, which may imply a thinner cover of microscopically rough regolith compared to other areas. Seasonal variations, as already noticed for the whole nucleus, were also observed. We identified some potential morphological changes near the landing site implying a total mass-loss of (4.7–7.0) × 105 kg. Small spots ranging from 0.1 to 27 m2 were observed close to Abydos before and after perihelion. Their estimated water ice abundance reaches 30–40 per cent locally, indicating fresh exposures of volatiles. Their lifetime ranges from a few hours up to three months for two pre-perihelion spots. The Abydos surroundings showed a low level of cometary activity compared to other regions of the nucleus. Only a few jets are reported originating nearby Abydos, including a bright outburst that lasted for about 1 h.

scholarly journals On the truncated Pareto distribution with applications

Open Physics ◽  
2008 ◽  
Vol 6 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lorenzo Zaninetti ◽  
Mario Ferraro
Keyword(s):  
Statistical Analysis ◽  
Probability Distribution ◽  
Pareto Distribution ◽  
Physical Mechanism ◽  
Pareto Tails ◽  
The Masses ◽  
Truncated Pareto

AbstractThe Pareto probability distribution is widely applied in different fields such us finance, physics, hydrology, geology and astronomy. This note deals with an application of the Pareto distribution to astrophysics and more precisely to the statistical analysis of masses of stars and of diameters of asteroids. In particular a comparison between the usual Pareto distribution and its truncated version is presented. Finally, a possible physical mechanism that produces Pareto tails for the distribution of the masses of stars is presented.

A characterization of the exponential distribution

1972 ◽  
Vol 9 (02) ◽  
pp. 457-461 ◽  
Author(s):  
M. Ahsanullah ◽  
M. Rahman
Keyword(s):  
Probability Distribution ◽  
Order Statistics ◽  
Lebesgue Measure ◽  
Random Variable ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Positive Random Variable ◽  
Absolutely Continuous ◽  
Necessary And Sufficient

A necessary and sufficient condition based on order statistics that a positive random variable having an absolutely continuous probability distribution (with respect to Lebesgue measure) will be exponential is given.

Inhalation of nail dust from onychomycotic toenails. Part I. Characterization of particles. 1984

1992 ◽  
Vol 82 (2) ◽  
pp. 111-115 ◽  
Author(s):  
C Abramson ◽  
J Wilton
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Total Mass ◽  
Particle Size Analysis ◽  
Dust Particles ◽  
Size Analysis ◽  
Scanning Electron

Nail dust particles were analyzed by scanning electron microscopy for size and topography. The percentage of "fines" that could be inhaled and deposited in the alveoli and bronchioles were determined by quantitative particle size analysis. Distribution representing the largest total mass was graphed between 1 and 2 microns. The authors found that 86% of nail dust would reach the bronchioles and alveoli, and 31% could be expected to deposit in these areas.

scholarly journals Kepler Object of Interest Network

2018 ◽  
Vol 615 ◽  
pp. A79 ◽  
Author(s):  
C. von Essen ◽  
A. Ofir ◽  
S. Dreizler ◽  
E. Agol ◽  
J. Freudenthal ◽  
...  
Keyword(s):  
Star System ◽  
Transiting Planets ◽  
Photometric Observations ◽  
First Results ◽  
Depth Study ◽  
Interesting Candidate ◽  
Site Network ◽  
The Masses ◽  
Long Timescales

During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler’s greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler’s unique work, we have organized the “Kepler Object of Interest Network” (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where Kepler did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend Kepler’s baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet–star system. While the simultaneous transit fitting of ground- andspace-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.

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