2,532 research outputs found
Finite size effects in the study of equation of state for the nuclei with skyrme force : a thesis presented in partial fulfilment of requirements for the degree of Master in Physics at Massey University, Palmerston North, New Zealand
The equation of state for symmetric nuclear matter and nite nuclei has been
investigated using self-consistent Hartree Fock approach. Several versions of Skyrme
e ective interaction and Hill-Wheeler formula are employed in the calculation. The
nite size e ect parameter aF , which is introduced into the Hill-Wheeler formula, is
determined by comparing theoretical calculations and experimental results for the zero
temperature properties. The dependence of aF on the e ective interaction employed
has been studied. It was found that di erent versions of Skyrme force lead to di erent
values for aF apart from SKI and SKIII which gave a similar value. Also, the aF values
obtained with Skyrme interaction were di erent from what was obtained with Gogny
force with the exception of SKV interaction which gave a value of aF = 0:35 identical
to the value obtained with D1 Gogny interaction. The critical points of the rst order
phase transition for the nuclear matter and nite size nuclei calculated with the several
versions of Skyrme force were di erent from each other. The largest value of critical
temperature for nuclear matter is given by SKV force as Tc = 39:45 MeV, while SKIII
interaction gives the smallest value as Tc = 21:65 MeV. Similarly, the largest value
of the critical density is given by SKV interaction. The critical points depend on the
number of nucleons in the system and Tc decreases as the number of nucleons in the
system decreases
Psychometric properties of two Islamic measures among young adults in Kuwait: the Sahin-Francis Scale of Attitude toward Islam and the Sahin Index of Islamic Moral Values
Given the importance of developing reliable and valid measures in the psychology of religion, and recent growing interest in developing empirical studies within an Islamic context, the present study discusses the properties of two specially designed instruments: the Sahin-Francis Scale of Attitude toward Islam and the Sahin Index of Islamic Moral Values. Data were provided by a sample of 1,199 students, selected from secondary schools in six educational districts in Kuwait. The sample comprised 603 males and 596 females; 812 were 17 years of age and 387 were 18 years of age. The data support the internal consistency reliability and construct validity of both instruments and commend them for further research
Studies on the mechanisms of action and physiological relevance of SOCS proteins
Understanding systemic biological pathways and the key cellular mechanisms that
dictate disease states, drug response, and altered cellular function in metabolic disorders
is a significant challenge. Research in the last 20 years have made it clear that tissue
communication, through the actions of endocrine, paracrine or autocrine factors play a
significant role in pathogenesis of complex multiorgan diseases such as the metabolic
syndrome. The actions of these factors are governed both at the site of production and
through mechanisms that regulate the sensitivity of target tissues.
The Suppressors of Cytokine Signaling (SOCS) proteins act as negative regulators of
the main cytokine and growth factor signaling pathways in multiple tissues and as such
have important physiological functions. The molecular basis for SOCS actions as well
as their role in the pathogenesis of metabolic diseases is just starting to be understood.
All SOCS proteins (SOCS1 to 7 and CIS) are characterized by the presence of
structural motifs called SOCS box and a SH2 domain. SOCS are thought to act as
substrate recognition subunits of multimeric Cullin/RING E3 ubiquitin ligase
complexes. It has been proposed that the SH2 domain mediates the recognition of
tyrosine phosphorylated signaling proteins to be targeted for ubiquitination and
subsequently, proteasomal degradation, thereby inhibiting cytokine signaling.
In this thesis we investigated the mechanisms of action of SOCS2 and SOCS6 in the
inhibition of cellular signaling and the physiological consequence of their actions. We
demonstrated that both SOCS2 and SOCS6 assemble a canonical ECS
(Elongin/Cullin/SOCS) complex through the interaction of SOCS box with Elongin B
and C, cullin 5 and Rbx2. We also demonstrated that SOCS2 and SOCS6 exert E3-
ligase activity towards the growth hormone (GH) receptor and cKIT proteins,
respectively. Our structural and binding studies confirmed the existence of substrate
binding motifs mainly in the SH2 domains and the N-terminal domain of both SOCSs.
The C-terminus harbours the cullin 5 recognition domain that controls both E3 ligase
activity of the complex as well as the SOCS stability. We proposed that extended target
recognition domain in the SOCS proteins may serve to broaden their specificity toward
various targets and hence their ability to regulate various signaling pathways. On the
other hand, the existence of a degradation signal within the Elongin C interacting
domain of SOCS proteins may serve to secure their timely actions avoiding
competition from SOCS that are not engaged in active E3 ubiquitin ligase complexes.
The patho-physiological role of SOCS2 was studied in SOCS2 knockout (SOCS2-/-)
mice. In line with the in vitro studies (paper I), we observed an increased GH
sensitivity in SOCS2-/- mice, demonstrated by low plasma GH/IGF1 ratio. In the liver,
this enhanced sensitivity was manifested through increased VLDL secretion and
reduced hepatic triglycerides levels. SOCS2-/- showed reduced hepatic steatosis upon
high fat feeding as compared to wild type littermates but also exhibited increased
adiposity and fat deposition in the skeletal muscles accompanied by profound systemic
insulin resistance. We also demonstrated the involvement of SOCS2 in the regulation
of inflammatory pathways. SOCS2-/- mice showed an exacerbated response to a high
fat diet, with increased expression of inflammatory cytokines such as IL-6, RANTES,
IL1β both in the liver and adipose tissue. We also identified possible mechanisms to
explain these phenomena by demonstrating that macrophages isolated from SOCS2-/-
mice showed higher phagocytic activity and higher LPS-induced NF-κB activity;
indicative of SOCS2 negative regulation of TLR4 signals.
Given the short half-life of SOCS proteins in the cells, the regulation of SOCS gene
transcription is an important mechanism to control their function. The nuclear receptor
LXR has regulatory functions on hepatic lipid metabolism that overlap with those
controlled by the GH. Therefore, in order to understand the molecular basis for possible
crosstalks between these two pathways, we studies how LXR ligands regulate the GH
receptor signaling in liver. We showed that LXR agonist downregulates STAT5b
protein levels and suppresses GH receptor activity in hepatocytes through a mechanism
involving SREBP1. The regulation by SREBP1 occurs through the modulation of
STAT5b protein stability and results in reduced expression of GH target genes such as
SOCS2. These results provide a plausible explanation for the hepatosteatosis observed
upon LXR agonist treatment in vivo.
In conclusion, through structural, in vivo and in vitro studies, we provide mechanistic
and functional data on SOCS2 and SOCS6; information that may lead to a better
understanding of the distinct physiological functions of these proteins. Given our
demonstration on the key role of ubiquitination on SOCS functions, future mechanistic
studies of SOCS2 and SOCS6 function should focus on the identification of
ubiquitination targets of these proteins. Are the physiological functions ascribed to
these proteins a result of the degradation of a few target proteins or do they have many
targets? If the later is the case, how is SOCS target-specificity structurally determined
and how is their activity regulated in time and cellular location? The demonstration that
SOCS2 regulate both GH receptor and TLR4 signaling offers system where these
questions can be addressed. At physiological levels, the SOCS2-/- mice constitute a
novel model system for the study of the metabolic syndrome with unique features that
are relevant to the human disease. In the SOCS2-/- mice, insulin resistance and
production of inflammatory cytokine are exacerbated by high fat feeding and associated
with obesity and deposition of triacylglycerides in the muscle. In these conditions
reduced accumulation of TG in liver is observed. This model presents opportunities for
future investigations aiming to distinguish between steatotic versus inflammatory
causes for insulin resistance
Infant mortality in Kuwait and problems of its solution
Currently, the health care system of Kuwait is one of the best in the Persian region. Medical services are provided free to all segments of the population.
Primary care is provided by health centers, the Centers for maternal and child health, school health center, ambulance and family doctors. The second level of health care provided by hospitals located in each region. And the highest, third level includes a large number of specialized clinics. In 1987 was opened globally unique Islamic Center of Medicine, which is practical and scientific object studied and used traditional methods of treatment.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3634
MULTIVARIATE MODELING OF COGNITIVE PERFORMANCE AND CATEGORICAL PERCEPTION FROM NEUROIMAGING DATA
State-of-the-art cognitive-neuroscience mainly uses hypothesis-driven statistical testing to characterize and model neural disorders and diseases. While such techniques have proven to be powerful in understanding diseases and disorders, they are inadequate in explaining causal relationships as well as individuality and variations. In this study, we proposed multivariate data-driven approaches for predictive modeling of cognitive events and disorders. We developed network descriptions of both structural and functional connectivities that are critical in multivariate modeling of cognitive performance (i.e., fluency, attention, and working memory) and categorical perceptions (i.e., emotion, speech perception). We also performed dynamic network analysis on brain connectivity measures to determine the role of different functional areas in relation to categorical perceptions and cognitive events. Our empirical studies of structural connectivity were performed using Diffusion Tensor Imaging (DTI). The main objective was to discover the role of structural connectivity in selecting clinically interpretable features that are consistent over a large range of model parameters in classifying cognitive performances in relation to Acute Lymphoblastic Leukemia (ALL). The proposed approach substantially improved accuracy (13% - 26%) over existing models and also selected a relevant, small subset of features that were verified by domain experts. In summary, the proposed approach produced interpretable models with better generalization.Functional connectivity is related to similar patterns of activation in different brain regions regardless of the apparent physical connectedness of the regions. The proposed data-driven approach to the source localized electroencephalogram (EEG) data includes an array of tools such as graph mining, feature selection, and multivariate analysis to determine the functional connectivity in categorical perceptions. We used the network description to correctly classify listeners behavioral responses with an accuracy over 92% on 35 participants. State-of-the-art network description of human brain assumes static connectivities. However, brain networks in relation to perception and cognition are complex and dynamic. Analysis of transient functional networks with spatiotemporal variations to understand cognitive functions remains challenging. One of the critical missing links is the lack of sophisticated methodologies in understanding dynamics neural activity patterns. We proposed a clustering-based complex dynamic network analysis on source localized EEG data to understand the commonality and differences in gender-specific emotion processing. Besides, we also adopted Bayesian nonparametric framework for segmentation neural activity with a finite number of microstates. This approach enabled us to find the default network and transient pattern of the underlying neural mechanism in relation to categorical perception. In summary, multivariate and dynamic network analysis methods developed in this dissertation to analyze structural and functional connectivities will have a far-reaching impact on computational neuroscience to identify meaningful changes in spatiotemporal brain activities
A think-aloud protocols investigation of lexico-semantic problems and problem-solving strategies among trainee English-Arabic translators.
SIGLEAvailable from British Library Document Supply Centre-DSC:DXN039294 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
The importance of ancillary insurance benefits by members of Medicare risk contract insurance plan
Thesis (D.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2000.Includes bibliographical references (leaves 63-75)
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