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Search Results: 1 - 10 of 504 matches for " Petros Kolovos "
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Cardiovascular Disease and Chronic Inflammation in End Stage Kidney Disease
Sofia Zyga,Petros Kolovos
International Journal of Caring Sciences , 2013,
Abstract: Background: Chronic Kidney Disease (CKD) is one of the most severe diseases worldwide. In patients affected by CKD, a progressive destruction of the nephrons is observed not only in structuralbut also in functional level. Atherosclerosis is a progressive disease of large and medium-sized arteries. It is characterized by the deposition of lipids and fibrous elements and is a common complication of the uremic syndrome because of the coexistence of a wide range of risk factors. High blood pressure, anaemia, insulin resistance, inflammation, high oxidative stress are some of the most common factors that cause cardiovascular disease and atherogenesis in patients suffering from End Stage Kidney Disease (ESRD). At the same time, the inflammatory process constitutes a common element in the apparition and development of CKD. A wide range of possible causes can justify the development of inflammation under uremic conditions. Such causes are oxidative stress, oxidation, coexistentpathological conditions as well as factors that are due to renal clearance techniques. Patients in ESRD and coronary disease usually show increased acute phase products. Pre-inflammatory cytokines, such as IL-6 and TNF-a, and acute phase reactants, such as CRP and fibrinogen, are closely related. The treatment of chronic inflammation in CKD is of high importance for the development ofthe disease as well as for the treatment of cardiovascular morbidity.Conclusions: The treatment factors focus on the use of renin-angiotensic system inhibitors, acetylsalicylic acid, statins and anti-oxidant treatment in order to prevent the action of inflammatorycytokines that have the ability to activate the mechanisms of inflammation.
Nursing Students' Perceptions, Beliefs and Attitudes: A First Study on Special Pedagogic Activities
Vassiliki Ioannidi,Petros Kolovos,Sofia Vasileiadou,Maria Malliarou
Global Journal of Health Science , 2011, DOI: 10.5539/gjhs.v3n1p40
Abstract: Background: Studying nursing students' opinions could be a useful guide for the formation of their professional role as well as their education and training. Aim: The present study's aim is to examine nurse students' opinion, beliefs and attitude regarding the concepts of health, health care, health education, health ethics, illness, safety in health care and quality in health care, in an educational environment which promotes cooperative activities in class. Methodology: Seventy four nurse students of the University of Peloponnese participated in the present study during the winter semester of 2008-2009. They were asked to describe shortly the meaning of the study concepts, writing down their opinion on a questionnaire that included six questions. Their answers were evaluated using the method of content analysis and sorted to exhaustive and mutually exclusive categories. Results: Nursing Students were asked to describe the meaning of the concept of health, health care, health education, health ethics, illness, safety in health care and quality in health care. The result of the students' opinion reveals the way they conceive their professional role, their education and their attitude in real working conditions and, therefore, the quality of the services they provide and how well prepared they are to demand and to put in a claim for the quality in health care. Conclusions: Further empirical research could aim to replicate or contradict these findings, using a larger sample and recruiting more university departments.
Nurse students' approach on concepts
Vassiliki Ioannidi,Petros Kolovos,Sofia Vasileiadou,Maria Malliarou
To Vima tou Asklipiou , 2011,
Abstract: Nurse Students' opinion regarding fundamental parameters of health while practicing health care defines their professional identity and for that reason, their opinion could give direction for the formation of their professional role and their education and training. Aim: The present study's aim is to examine nurse students' opinion, beliefs and attitude regarding the concepts of "illness", "safety in health care" and "quality in health care" while being in an educational environment which promotes cooperative class activities. Methodology: In this pilot study participated thirty six (36) undergraduate students of Department of Nursing University Peloponnese in the frame of course "Introduction in Nursing Science". Students' answers evaluated using content analysis method and the analysis was based on the latent content of students' answers. Therefore, the texts which were selected as the analysis units were afterwards shortened by using the "abstraction" method. In other words, the method that was followed included the data extraction with base of their content and afterwards those data were categorized and classified in wider subcategories. In order to quantify provided data, these subcategories were unified in wider categories-subjects which in turn unify all the individual meanings. Results: All thirty-six (36) students who filled the questionnaire answered that the meaning of illness concerns so much the physical as long as the mental status of a person. Students were then called to define the meaning of concept "safety in health care" and from their answers using content analysis method, 78 reports resulted. Students also answered in the question "what means safety in health care", that safety concerns both health care professionals and all the rest health care users. In the second category were categorized the students' answers that concerned in the way with who, at their opinion, is ensured the safety in the provided health care, in other words which are the necessary conditions that argue safety in health care. In the third category were categorized the participants' answers concerning the result of care that proves safety, that is to say, which is the evidence that proves safety existence in benefit of health care. Students were here called to answer what means in their opinion the concept "quality in health services". From their answers, who were analyzed using content analysis method and categorized in four categories-subjects, resulted 72 reports. Conclusions: Nurse students' and therefore future health professionals' answers concerning the
Inter-Relationship between Testicular Dysgenesis and Leydig Cell Function in the Masculinization Programming Window in the Rat
Sander van den Driesche, Petros Kolovos, Sophie Platts, Amanda J. Drake, Richard M. Sharpe
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030111
Abstract: The testicular dysgenesis syndrome (TDS) hypothesis proposes that maldevelopment of the testis, irrespective of cause, leads to malfunction of the somatic (Leydig, Sertoli) cells and consequent downstream TDS disorders. Studies in rats exposed in utero to di(n-butyl) phthalate (DBP) have strongly supported the TDS concept, but so far no direct evidence has been produced that links dysgenesis per se to somatic cell dysfunction, in particular to androgen production/action during the ‘masculinization programming window’ (MPW; e15.5–e18.5). Normal reproductive tract development and anogenital distance (AGD) are programmed within the MPW, and TDS disorders arise because of deficiencies in this programming. However, DBP-induced focal testicular dysgenesis (Leydig cell aggregation, ectopic Sertoli cells, malformed seminiferous cords) is not evident until after the MPW. Therefore, we used AGD as a read-out of androgen exposure in the MPW, and investigated if this measure was related to objectively quantified dysgenesis (Leydig cell aggregation) at e21.5 in male fetuses exposed to vehicle, DBP (500 or 750 mg/kg/day) or the synthetic glucocorticoid dexamethasone (Dex; alone or plus DBP-500) from e15.5–e18.5 (MPW), e13.5–e20.5 or e19.5–e20.5 (late window). Dysgenesis was found only in animals exposed to DBP during the MPW, and was negatively correlated (R2 = ?0.5) with AGD at e21.5 and at postnatal day 8, irrespective of treatment period. Dysgenesis was also negatively correlated (R2 = –0.5) with intratesticular testosterone (ITT) at e21.5, but only when treatments in short windows (MPW, late window) were excluded; the same was true for correlation between AGD and ITT. We conclude that AGD, reflecting Leydig cell function solely within the MPW, is strongly related to focal dysgenesis. Our results point to this occurring because of a common early mechanism, targeted by DBP that determines both dysgenesis and early (during the MPW) fetal Leydig cell dysfunction. The findings provide strong validation of the TDS hypothesis.
Enhancers and silencers: an integrated and simple model for their function
Petros Kolovos, Tobias A Knoch, Frank G Grosveld, Peter R Cook, Argyris Papantonis
Epigenetics & Chromatin , 2012, DOI: 10.1186/1756-8935-5-1
Abstract: The complex linear organisation [1] of many metazoan genomes encodes regulatory sequences that can be categorised into two major groups: enhancers and silencers. Enhancers are short motifs that contain binding sites for transcription factors; they activate their target genes without regard to orientation and often over great separations in cis or in trans [2]. Silencers suppress gene expression [3] and/or confine it within specific chromatin boundaries (and thus are also called 'insulators') [4]. The interplay between these contrasting regulatory elements, their target promoters and epigenetic modifications at all levels of three-dimensional organisation (that is, nucleosomes, chromatin fibres, loops, rosettes, chromosomes and chromosome location) [5-9] fine-tune expression during development and differentiation. However, the mechanisms involved in this interplay remain elusive, although some can be computationally predicted [10]. Although enhancers and silencers have apparently opposite effects, accumulating evidence suggests they share more properties than intuition would suggest [11]. Herein we try to reconcile their apparently disparate modes of action. We suggest they act by tethering their target promoters close to, or distant from, hot spots of nucleoplasmic transcription (known as 'transcription factories') as they produce noncoding transcripts (ncRNAs) [12-15].Enhancers were characterised almost 30 years ago [16], but their functional definitions vary because of their flexibility of action (whether in cis or in trans) [17,18], position (relative orientation and/or distance) and genomic location (in gene deserts, introns and/or untranslated regions) [2]. Although sequence conservation between species can, in some cases, be an efficient predictor of enhancer identity, there are examples where genes with identical expression patterns in different species rely on enhancers that bear no similarities [19]. Within a single genome, however, sensitivity to DNase I a
Comment on "Hierarchical Bayesian space-time interpolation versus spatio-temporal BME approach" by Hussain et al. (2010)
A. Kolovos
Advances in Geosciences (ADGEO) , 2010,
Abstract: No abstract available.
Pre-B Cell Receptor Signaling Induces Immunoglobulin κ Locus Accessibility by Functional Redistribution of Enhancer-Mediated Chromatin Interactions
Ralph Stadhouders,Marjolein J. W. de Bruijn,Magdalena B. Rother,Saravanan Yuvaraj,Claudia Ribeiro de Almeida,Petros Kolovos,Menno C. Van Zelm,Wilfred van Ijcken,Frank Grosveld,Eric Soler,Rudi W. Hendriks
PLOS Biology , 2014, DOI: 10.1371/journal.pbio.1001791
Abstract: During B cell development, the precursor B cell receptor (pre-BCR) checkpoint is thought to increase immunoglobulin κ light chain (Igκ) locus accessibility to the V(D)J recombinase. Accordingly, pre-B cells lacking the pre-BCR signaling molecules Btk or Slp65 showed reduced germline Vκ transcription. To investigate whether pre-BCR signaling modulates Vκ accessibility through enhancer-mediated Igκ locus topology, we performed chromosome conformation capture and sequencing analyses. These revealed that already in pro-B cells the κ enhancers robustly interact with the ~3.2 Mb Vκ region and its flanking sequences. Analyses in wild-type, Btk, and Slp65 single- and double-deficient pre-B cells demonstrated that pre-BCR signaling reduces interactions of both enhancers with Igκ locus flanking sequences and increases interactions of the 3′κ enhancer with Vκ genes. Remarkably, pre-BCR signaling does not significantly affect interactions between the intronic enhancer and Vκ genes, which are already robust in pro-B cells. Both enhancers interact most frequently with highly used Vκ genes, which are often marked by transcription factor E2a. We conclude that the κ enhancers interact with the Vκ region already in pro-B cells and that pre-BCR signaling induces accessibility through a functional redistribution of long-range chromatin interactions within the Vκ region, whereby the two enhancers play distinct roles.
Existence and Uniqueness of Global Smooth Solutions for Vlasov Maxwell Equations  [PDF]
Lukas Degu Petros
Advances in Pure Mathematics (APM) , 2018, DOI: 10.4236/apm.2018.81005
Abstract: Global existence of classical solutions to the relativistic Vlasov-Maxwell system, given sufficiently regular initial data, is a long-standing open problem. The aim of this project is to present in details the results of a paper published in 1986 by Robert Glassey and Walter Strauss. In that paper, a sufficient condition for the global existence of a smooth solution to the relativistic Vlasov-Maxwell system is derived. In the following, the resulting theorem is proved by taking initial data \"\", \"\". A small data global existence result is presented as well.
Stability Analysis and Stochastic SI Modelling of Endemic Diseases  [PDF]
Desalegn Petros Kelkile
Advances in Pure Mathematics (APM) , 2018, DOI: 10.4236/apm.2018.85030
Abstract: In this paper, we study a stochastic epidemic model in Meta-population setting. The stochastic model is obtained from the deterministic model by set up random perturbations about the endemic equilibrium state. The outcome of random perturbations on the stability actions of endemic equilibrium is discussed. Stability of the two equilibriums is studied using the Lyapunov function.
Characterization of Rational Numbers Using Kronecker’s Orbit: A Didactic Approach  [PDF]
Petros-Stylianos Marsellos
Creative Education (CE) , 2018, DOI: 10.4236/ce.2018.915193
Abstract: For every real number x, we define as integer part the biggest integer k so that kx and is expressed [x]. The difference of the number from its integral part is defined as decimal part of x and expressed with \"\". Consequently, for every x, the Kronecker’s orbit is defined, namely the set \"\". Through Kronecker’s orbit, rational numbers are characterized as the numbers whose orbit is a bounded set, while irrational numbers are characterized as the numbers whose orbit is a dense set. Using this fundamental theoretical result and utilizing a computer, a didactic approach was established, initially referring to the definition of rational numbers as fraction equivalence classes and basically to the segregation of rational and irrational numbers. This didactic approach also incorporates elements of ancient Greek mathematics history. The proposition was applied to students and was evaluated.
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