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Search Results: 1 - 10 of 199387 matches for " Konstantinos N. Blazakis "
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Whole cell tracking through the optimal control of geometric evolution laws
Konstantinos N. Blazakis,Anotida Madzvamuse,Constantino-Carlos Reyes-Aldasoro,Vanessa Styles,Chandrasekhar Venkataraman
Mathematics , 2015,
Abstract: Cell tracking algorithms which automate and systematise the analysis of time lapse image data sets of cells are an indispensable tool in the modelling and understanding of cellular phenomena. In this study we present a theoretical framework and an algorithm for whole cell tracking. Within this work we consider that "tracking" is equivalent to a dynamic reconstruction of the whole cell data (morphologies) from static image datasets. The novelty of our work is that the tracking algorithm is driven by a model for the motion of the cell. This model may be regarded as a simplification of a recently developed physically meaningful model for cell motility. The resulting problem is the optimal control of a geometric evolution law and we discuss the formulation and numerical approximation of the optimal control problem. The overall goal of this work is to design a framework for cell tracking within which the recovered data reflects the physics of the forward model. A number of numerical simulations are presented that illustrate the applicability of our approach.
The emerging modern face of mood disorders: a didactic editorial with a detailed presentation of data and definitions
Konstantinos N Fountoulakis
Annals of General Psychiatry , 2010, DOI: 10.1186/1744-859x-9-14
Abstract: The ancient Greeks Hippocrates (460 to 357 BC), Galen (131 to 201 AD) and Areteus from Kappadokia introduced the terms melancholia and mania. Hippocrates was the first to describe melancholia, which is the Greek word for 'black bile', and simultaneously postulated a biochemical origin according to the scientific frame of that era, linking it to Saturn and the autumn. The term 'mania' was used to describe a broad spectrum of excited psychotic states. Soranus from Ephesus was the first to describe mixed states. Manic depressive illness has also been known since antiquity and Aretaeus of Cappadocia (2nd century AD) is considered to be the first to strongly connect melancholy with mania and make a description of manic episodes very close to the modern approach, including psychotic features and seasonality. Another interesting element in the theories that emerged during antiquity was the concept of temperament, which was originally based on harmony and balance of the four humours, of which the sanguine humour was considered to be the healthiest but also predisposing to mania. The melancholic temperament was linked to black bile and was considered to predispose to melancholia. Since the time of Aristotle (384 to 322 BC), the melancholic temperament was linked to creativity.Later, the Arab scholars dominated (Ishaq Ibn Imran, Avicenna and others) in particular during the 10th and 11th centuries AD. In 1621, Robert Burton wrote the first English language text, the Anatomy of Melancholy. Later, the works of Jean-Philippe Esquirol (1772 to 1840), Benjamin Rush (1745 to 1813), Henry Maudsley (1835 to 1918), Jean-Pierre Falret (1794 to 1870) and Jules Gabriel Francois Baillarger (1809 to 1890) finally established the connection between depression and mania. Eventually, Emil Kraepelin (1856 to 1926) established manic depressive illness as a nosological entity by separating it from schizophrenia on the basis of heredity, longitudinal follow-up and a supposed favourable outcome. I
Disruption of biological rhythms as a core problem and therapeutic target in mood disorders: the emerging concept of 'rhythm regulators'
Konstantinos N Fountoulakis
Annals of General Psychiatry , 2010, DOI: 10.1186/1744-859x-9-3
Abstract: Biological rhythms have always been considered to be disrupted in depression [1]. In the seminal paper by Akiskal and McKinney [2] it has been concluded that depression is related to hyperarousal, because depressive patients have lower threshold for awakening, rapid eye movement (REM) sleep disorders and loss of delta waves related sleep, which is the deepest stage of non-REM sleep. By 'hyperarousal', it is denoted that depressed patients manifest both higher reactivity to environmental stimuli and sympathetic nervous system (SNS) hyperactivity. According to this approach, sleep disorders are considered in the frame of higher vigilance [3]. Some authors reject this theory and suggest that only somatisation can involve altered central nervous system (CNS) processing (hyperarousal) of somatic stimuli [4]. Theoretically, a disturbance of biological rhythms could be a core feature in the etiopathogenesis of depression [5-7].However, from a clinical point of view depression is not a uniform clinical entity. Even for unipolar depression it is not known whether it is a single disorder or a spectrum of different disorders with overlapping clinical manifestations. Clinically, depressed patients do not manifest sleep disorders alone (difficulty in initiating or sustaining sleep or low sleep quality). The same patients, when awake, manifest concentration difficulties, reduced psychomotor activity, fatigue, somnolence and so on, and these symptoms could be independent from the sleep they experienced the previous night (that is, they are not always consequences of poor sleeping).Melancholic patients in particular typically manifest sleep disorders during the night (insomnia) and fatigue, concentration difficulties and anhaedonia with a lack of prominent anxiety during the daytime. These could be suggestive of a reduction of the arousal level variation span. According to this theory, the arousal level is not sufficiently reduced during the night so as to lead to normal sleep, whi
Oil Spill Detection by SAR Images: Dark Formation Detection, Feature Extraction and Classification Algorithms
Konstantinos N. Topouzelis
Sensors , 2008, DOI: 10.3390/s8106642
Abstract: This paper provides a comprehensive review of the use of Synthetic Aperture Radar images (SAR) for detection of illegal discharges from ships. It summarizes the current state of the art, covering operational and research aspects of the application. Oil spills are seriously affecting the marine ecosystem and cause political and scientific concern since they seriously effect fragile marine and coastal ecosystem. The amount of pollutant discharges and associated effects on the marine environment are important parameters in evaluating sea water quality. Satellite images can improve the possibilities for the detection of oil spills as they cover large areas and offer an economical and easier way of continuous coast areas patrolling. SAR images have been widely used for oil spill detection. The present paper gives an overview of the methodologies used to detect oil spills on the radar images. In particular we concentrate on the use of the manual and automatic approaches to distinguish oil spills from other natural phenomena. We discuss the most common techniques to detect dark formations on the SAR images, the features which are extracted from the detected dark formations and the most used classifiers. Finally we conclude with discussion of suggestions for further research. The references throughout the review can serve as starting point for more intensive studies on the subject.
Elderly and Prostate Cancer Screening
Konstantinos N Stamatiou
Urology Journal , 2011,
Abstract: PURPOSE: To discuss the issue of screening for prostate cancer in elderly individuals. The impact of life expectancy on the choice of treatment in both patients and health care providers has been investigated as well. MATERIALS AND METHODS: We identified studies published from 1990 onwards by searching the MEDLINE database of the National Library of Medicine. Initial search terms were “localized prostate cancer” and “early stage prostate cancer” combined with “elderly patients, life expectancy, palliative, curative, quality of life, watchful waiting, radical prostatectomy, brachytherapy, and external beam radiotherapy”. RESULTS: Despite the decrease in prostate carcinoma-specific mortality, the use of prostate-specific antigen (PSA) has been shown to increase the prostate cancer detection rate with a shift to detection at earlier and less invasive pathological stages, overriding concerns about over-diagnosis and overtreating. However, PSA screening is mainly offered to younger individuals, and older patients are more likely to have progressive disease and high-risk prostate cancer at diagnosis. Given that PSA screening diagnoses mainly curable, early prostate cancer, screening decision could be offered to otherwise healthy elderly patients who are likely to benefit from aggressive treatment. CONCLUSION: Prostate-specific antigen screening is not officially recommended and most scientific associations promote shared decision making. While PSA screening decision is currently based on physician’s judgment, it is clear that a strict age cut-off of 75 years reduces over-screening, but also prohibits screening in healthy older men with a long life expectancy.
Remission in different domains of symptoms and deficits
Fountoulakis Konstantinos N
Annals of General Psychiatry , 2006, DOI: 10.1186/1744-859x-5-s1-s30
Abstract:
An explicit formula for the prime counting function
Konstantinos N. Gaitanas
Mathematics , 2013, DOI: 10.4169/amer.math.monthly.122.03.283
Abstract: In this paper we use a theorem first proved by S.W.Golomb and a famous inequality by J.B. Rosser and L.Schoenfeld in order to prove that there exists an exact formula for $\pi(n)$ which holds infinitely often.
On sequences of natural numbers having pairwise relatively prime terms
Konstantinos N. Gaitanas
Mathematics , 2015,
Abstract: We prove some theorems which give sufficient conditions for the existence of prime numbers among the terms of a sequence which has pairwise relatively prime terms.
Efficacy and safety of aripiprazole in the treatment of bipolar disorder: a systematic review
Konstantinos N Fountoulakis, Eduard Vieta
Annals of General Psychiatry , 2009, DOI: 10.1186/1744-859x-8-16
Abstract: A systematic Medline and repositories search concerning the usefulness of aripiprazole in bipolar disorder was performed, with the combination of the words 'aripiprazole' and 'bipolar'.The search returned 184 articles and was last updated on 15 April 2009. An additional search included repositories of clinical trials and previous systematic reviews specifically in order to trace unpublished trials. There were seven placebo-controlled randomised controlled trials (RCTs), six with comparator studies and one with add-on studies. They assessed the usefulness of aripiprazole in acute mania, acute bipolar depression and during the maintenance phase in comparison to placebo, lithium or haloperidol.Aripiprazole appears effective for the treatment and prophylaxis against mania. The data on bipolar depression are so far negative, however there is a need for further study at lower dosages. The most frequent adverse effects are extrapyramidal signs and symptoms, especially akathisia, without any significant weight gain, hyperprolactinaemia or laboratory test changes.The treatment of bipolar illness started with lithium and Frederik Lange in the late 19th century [1]; later John Cade in 1949 [2-4] and Mogens Schou with Poul Christian Baastrup in the 1970s established its effectiveness [5-10]. Its long-term effects are still a matter of debate [11]. Anticonvulsants are also considered to be useful in the treatment of bipolar illness. In spite of what many clinicians believe, there is no class effect for this group in bipolar disorder, since only valproate carbamazepine and lamotrigine have strong data support. The use and usefulness of antidepressant agents in bipolar disorder (BD) is controversial. Guidelines suggest their cautious use and always in combination with an antimanic agent [12]. This is because antidepressants are believed to induce switching to mania or hypomania [13-16], mixed episodes [17] and rapid cycling, while research suggests that the use of antimanic agents
Current Surgical Aspects of Palliative Treatment for Unresectable Pancreatic Cancer
Konstantinos Karapanos,Iakovos N. Nomikos
Cancers , 2011, DOI: 10.3390/cancers3010636
Abstract: Despite all improvements in both surgical and other conservative therapies, pancreatic cancer is steadily associated with a poor overall prognosis and remains a major cause of cancer mortality. Radical surgical resection has been established as the best chance these patients have for long-term survival. However, in most cases the disease has reached an incurable state at the time of diagnosis, mainly due to the silent clinical course at its early stages. The role of palliative surgery in locally advanced pancreatic cancer mainly involves patients who are found unresectable during open surgical exploration and consists of combined biliary and duodenal bypass procedures. Chemical splanchnicectomy is another modality that should also be applied intraoperatively with good results. There are no randomized controlled trials evaluating the outcomes of palliative pancreatic resection. Nevertheless, data from retrospective reports suggest that this practice, compared with bypass procedures, may lead to improved survival without increasing perioperative morbidity and mortality. All efforts at developing a more effective treatment for unresectable pancreatic cancer have been directed towards neoadjuvant and targeted therapies. The scenario of downstaging tumors in anticipation of a future oncological surgical resection has been advocated by trials combining gemcitabine with radiation therapy or with the tyrosine kinase inhibitor erlotinib, with promising early results.
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