122 research outputs found
Morphology and digitally aided morphometry of the human paracentral lobule
The human paracentral lobule, the junction of the precentral and postcentral gyri at the medial hemispheric surface, contains several important functional regions, and its variable morphology requires exact morphological and quantitativedata. In order to obtain precise data we investigated the morphology of the paracentral lobule and quantified its visible (extrasulcal) surface. This surface corresponds to commonly used magnetic resonance imaging scout images. We studied84 hemispheres of adult persons (42 brains; 26 males and 16 females; 20ā65 years) fixed in neutral formalin for at least 4 weeks. The medial hemispheric surface was photographed at standard distance and each digital photo was calibrated.Using the intercommissural line system (commissura anterior-commissura posterior or CA-CP line), we performed standardised measurements of the paracentral lobule. Exact determination of its boundaries and morphological typeswas followed by digital morphometry of its extrasulcal surface using AutoCAD software. We found two distinct morphological types of the human paracentral lobule: continuous type, which was predominant (95.2%), and rare segmented type (4.8%). In hemispheres with segmented cingulate sulcus we also found theshort transitional lobulo-limbic gyrus (13.1%). The mean extrasulcal surface of the left paracentral lobule was significantly larger, both in males (left 6.79 cm2 vs. right 5.76 cm2) and in females (left 6.05 cm2 vs. right 5.16 cm2). However, even larger average surfaces in males were not significantly different than the same in females. Reported morphological and quantitative data will be useful during diagnostics and treatment of pathologies affecting the human paracentral lobule, and in further studies of its cytoarchitectonic and functional parcellations
Sex differences of human corpus callosum revealed by polar coordinate system: magnetic resonance imaging study
Background: Evaluation of morphological and size changes related to various pathological conditions of the corpus callosum (CC) requires the data about sex dimorphism of the CC. The purpose of our study is to define potential morphological sex differences of the CC by the use of polar coordinate system as a system of measurements.
Materials and methods: After division of the CC into three equal segments by the use of polar coordinate system, we investigated the length of the hemisphere (A-Aā), the CC size as its midsagittal section area (CCA), the size of its segments (C1, C2, C3), thickness of the thinnest part of the CC (TCC) and the angular coordinate (a angle) of dorsal point of the TCC in a sample of 30 human brains magnetic resonance images (15 males and 15 females, age 20ā50 years).
Results: We found significantly larger CCA, C3 segment and the TCC in males. Statistically significant correlation in both, males and females, was found between parameters of the CCA and of all of its segments (C1, C2, C3), the C1 and C2, the C2 and C3 segments, as well as like as between the C2 and TCC. Sex differences were also in findings of significant correlation between the C1 and C3 segments, between CCA and TCC, and of significant negative correlation between the a angle and A-Aā only in females.
Conclusions: We concluded that the use of polar coordinate system appropriately reflects the anatomical and encephalometric characteristics of human CC
Supplementary data for article : Panic, V. V.; Seslija, S. I.; Popovic, I. G.; Spasojevic, V. D.; Popovic, A. R.; Nikolic, V. B.; Spasojevic, P. M. Simple One-Pot Synthesis of Fully Biobased Unsaturated Polyester Resins Based on Itaconic Acid. Biomacromolecules 2017, 18 (12), 3881ā3891. https://doi.org/10.1021/acs.biomac.7b00840
Supporting information for: [https://doi.org/10.1021/acs.biomac.7b00840]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2568]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3058
Sex and level differences in the diameters of extradural segment of vertebral artery: computed tomography angiographic study
Background: We investigated diameters of prevertebral ā V1, and atlantic ā V3 parts of extradural segment of vertebral artery (VA). Variable results from the literaturÄ about VA diameters reflect variety of diagnostic and imaging methods, various sample sizes, different levels of measurements, and lack of possible specific ethnic, regional or genetic data. Additionally, the data are often without distinctions of left-right or of sex.
Materials and methods: For this computed tomography (CT) angiographic study 91 adult people (182 VAs) of both sexes (47 males and 44 females) and of age between 33 and 75 years were selected. Diameters were measured at fixed predefined points of VA, marked as inferior (A) point (at V1 part in region of VA origin), as middle (B) point (the end of V1 part), and superior (C) point, at V3 part ā 5 mm before VA penetrated the dura. Inferior (A) and middle (B) points actually represent locations at beginning (A) and at terminal (B) regions of V1 part of VA, and superior point C represents terminal part of V3.
Results: In total sample ipsilateral (both left [L] and right [R] sided) diameters on investigated levels of VA showed progressive and highly significant decreases. The mean values were on the right side at point A ā 3.63 mm, at B point ā 3.31 mm, and at C point ā 3.08 mm. On the left side, mean values were at point A ā 3.76 mm, at B point ā 3.50 mm, and at point C ā 3.21 mm. Pattern of increasing sex differences in diameters of VA, was ranging from no differences (point A), trough significant (point B), to highly significant differences (point C). For inferior point (A) we did not find significant differences in VA diameters between males (R 3.78 mm; L 3.89 mm) and females (R 3.50 mm; L 3.62 mm), in middle (B) point sex differences were significant (males: R 3.44 mm, L 3.66 mm; females: R 3.18 mm, L 3.33 mm) and in most superior point (C) differences were highly significant (males: R 3.278 mm, L 3.39 mm; females: R 2.88 mm, L 3.01 mm). However, we did not find significant intrasex (in males or in females) left-right differences in mean values of VA diameters for all three investigated levels.
Conclusions: Our findings, as the first data about diameters of VA systematically obtained by CT angiography in the population of western Balkans and wider, suggest that in design of future studies of VA diameters is necessary to analyse separately the data for sex, as well as to use defined standard levels
Stable, metastable and unstable states in the mean-field RFIM at T=0
We compute the probability of finding metastable states at a given field in
the mean-field random field Ising model at T=0. Remarkably, this probability is
finite in the thermodynamic limit, even on the so-called ``unstable'' branch of
the magnetization curve. This implies that the branch is reachable when the
magnetization is controlled instead of the magnetic field, in contrast with the
situation in the pure system.Comment: 10 pages, 3 figure
Internal carotid and vertebral arteries diameters and their interrelationships to sex and left/right side
Background: The available anatomical data about diameters of inflow vessels to the circle of Willis reflect various diagnostic and imaging methods used, sample sizes, levels of measurements, and lack of possible specific ethnic, regional or genetic data. Additionally, the data are often without distinctions about left-right or sex.
Materials and methods: Therefore, using computed tomography angiography (CTA) we investigated diameters of internal carotid (ICA) and vertebral (VA) arteries in 70 adult persons (28ā75 years) of both sexes (34 males and 36 females), at predefined cervical parts of ICA (2 cm above carotid bifurcation) and of VA (5 mm before VA penetrated the dura).
Results: Sex differences were expressed as highly significant larger diameters of left VA (LVA) in males (3.49 mm) than in females (3.00 mm), and as significantly larger diameters of right VA (RVA) in males (3.20 mm) than in females (2.82 mm), as well as of right ICA (RICA) diameters in males (5.04 mm) than in females (4.56 mm), but without such difference for left ICA (LICA) between males (4.82 mm) and females (4.60 mm). Intrasex (in males or in females) left-right differences of ICA and VA diameters were not significant. Significant positive correlations were found in females between RICA and RVA, and in males between RICA and LICA. Calculated mean sum of ipsilateral diameters of right arteries (RAA = RICA + RVA) was in males 8.25 mm, in females 7.38 mm, and of left arteries (LAA = LICA + LVA) was in males 8.31, and in females 7.60 mm, without statistically significant difference between RAA and LAA, neither in males, nor in females. Statistically highly significant larger sums of diameters were in males than in females for both, RAA and LAA.
Conclusions: Our findings, as the first data about diameters of ICA and VA systematically obtained by CTA in the population of western Balkans, suggest that in the studies of these diameters is absolutely necessary to analyse separately the data for sex, and to use defined standard levels
Energy constrained sandpile models
We study two driven dynamical systems with conserved energy. The two automata
contain the basic dynamical rules of the Bak, Tang and Wiesenfeld sandpile
model. In addition a global constraint on the energy contained in the lattice
is imposed. In the limit of an infinitely slow driving of the system, the
conserved energy becomes the only parameter governing the dynamical
behavior of the system. Both models show scale free behavior at a critical
value of the fixed energy. The scaling with respect to the relevant
scaling field points out that the developing of critical correlations is in a
different universality class than self-organized critical sandpiles. Despite
this difference, the activity (avalanche) probability distributions appear to
coincide with the one of the standard self-organized critical sandpile.Comment: 4 pages including 3 figure
Average shape of fluctuations for subdiffusive walks
We study the average shape of fluctuations for subdiffusive processes, i.e.,
processes with uncorrelated increments but where the waiting time distribution
has a broad power-law tail. This shape is obtained analytically by means of a
fractional diffusion approach. We find that, in contrast with processes where
the waiting time between increments has finite variance, the fluctuation shape
is no longer a semicircle: it tends to adopt a table-like form as the
subdiffusive character of the process increases. The theoretical predictions
are compared with numerical simulation results.Comment: 4 pages, 6 figures. Accepted for publication Phys. Rev. E (Replaced
for the latest version, in press.) Section II rewritte
Supplementary data for article : Panic, V. V.; Seslija, S. I.; Popovic, I. G.; Spasojevic, V. D.; Popovic, A. R.; Nikolic, V. B.; Spasojevic, P. M. Simple One-Pot Synthesis of Fully Biobased Unsaturated Polyester Resins Based on Itaconic Acid. Biomacromolecules 2017, 18 (12), 3881ā3891. https://doi.org/10.1021/acs.biomac.7b00840
Supporting information for: [https://doi.org/10.1021/acs.biomac.7b00840]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2568]Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/3058
Nonuniversal scaling behavior of Barkhausen noise
We simulate Barkhausen avalanches on fractal clusters in a two-dimensional
diluted Ising ferromagnet with an effective Gaussian random field. We vary the
concentration of defect sites and find a scaling region for moderate
disorder, where the distribution of avalanche sizes has the form . The exponents for size
and for length distribution, and the fractal dimension of
avalanches satisfy the scaling relation .
For fixed disorder the exponents vary with driving rate in agreement with
experiments on amorphous Si-Fe alloys.Comment: 5 pages, Latex, 4 PostScript figures include
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