Ανάπτυξη μεθοδολογίας προβλεπτικού ελέγχου για δίκτυα διανομής ηλεκτρικής ενέργειας

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Συστήματα Αυτοματισμού

On the stability of equilibrium for a reformulated foreign trade model of three countries

In this paper, we study the stability of equilibrium for a foreign trade model consisting of three countries. As the gravity equation has been proven an excellent tool of analysis and adequately stable over time and space all over the world, we further enhance the problem to three masses. We use the basic Structure of Heckscher-Ohlin-Samuelson model. The national income equals consumption outlays plus investment plus exports minus imports. The proposed reformulation of the problem focus on two basic concepts: (1) the delay inherited in our economic variables and (2) the interaction effect along the three economies involved. Stability and stabilizability conditions are investigated while numerical examples provide further insight and better understanding. Finally, a generalization of the gravity equation is somehow obtained for the model

A brief review of Valsalva retinopathy

Background: Valsalva retinopathy is a specific type of retinopathy that appears following an acute rise in intrathoracic or intra-abdominal pressure. This review focuses on current literature and future directions for the diagnosis and management of Valsalva retinopathy. Methods: In this brief review, the literature was searched to provide an extensive general and updated description of Valsalva retinopathy, focusing on its management and prognosis. Selected articles are summarized to present the etiology, general pathology, pathophysiology, symptoms, signs, diagnosis, differential diagnosis, treatment, and prognosis of Valsalva retinopathy. Results: The main symptom of Valsalva retinopathy is loss of visual acuity following exertion. This is caused by the rupture of small superficial vessels in the macula and perimacular areas, leading to extravasation of blood. No link between age, sex, or race has been found, although fundus vessel abnormalities pose some predisposition to the disease. During fundoscopy, Valsalva retinopathy appears most frequently as well-defined preretinal hemorrhages confined to the sub-internal limiting membrane (ILM) or subhyaloid space. If ILM rupture occurs, hyaloid hemorrhage can appear. Diagnosis is based on the patient’s medical history and a standard examination. Usually, only observation of the patient is required, with the hemorrhage resolving within weeks to months. In cases of large premacular hemorrhage or large sub-ILM/subhyaloid hemorrhage, vitrectomy or Nd:YAG krypton laser membranotomy can be performed. Conclusions: Of all the aspects of Valsalva retinopathy that might trouble the physician, the most challenging features are differential diagnosis and the choice of optimal treatment. Therapeutic strategies for Valsalva retinopathy can be either conservative or based on Nd:YAG laser membranotomy and/or vitrectomy. All methods seem to have good outcomes. However, physicians should not be afraid of advancing beyond conservative therapy, especially in the event of persistent premacular hemorrhage, which could lead to permanent retinal damage if valuable time is lost, even after vitrectomy

Effect of Salt Stress on Three Green Bean (Phaseolus vulgaris L.) Cultivars

Agriculture is increasingly forced to utilize marginal waters to meet its increasing demands, which in turn increases the risks of soil salinization and yield reduction in the arid and semi-arid areas of the Mediterranean basin. Given that the bean is an extremely salt sensitive species, the purpose of the present work was to study the effect of 0 and 75 mM sodium chloride (NaCl) on leaf characteristics, growth, pod yield and ion accumulation of three green bean (Phaseolus vulgaris L.) cultivars ('Corallo Nano, 'Romano Bush Plaja' and 'Starazagorski'), widely used in Greece. Plants were grown in a greenhouse of Technological Educational Institute of Peloponnese in Messinia, Southern Greece, from April to June 2014, in hydroponics. The experimental design was the factorial completely randomized one with five replications; each replication consisted of the three plants grown on the same rockwool slab. The results of the majority of growth and yield parameters determined showed the superiority of 'Corallo' over 'Romano' whereas 'Starazagorski' tolerance was found to be intermediate. 'Corallo' tolerated NaCl salinity better due to its capacity for Na retention in the roots and maintaining appropriate K/Na and Ca/Na ratios, limiting the accumulation of toxic ions into actively growing shoots. The salt sensitivity of 'Romano' was related to its higher concentration of Na in the leaves and lower in the roots, to the greater decrease of the leaf number and leaf water content, as well as to the specific leaf area increase compared to the other two cultivars under saline conditions

Role of intestinal microbiome in the pathogenesis of age-related macular degeneration

Background: The microbiome is strongly linked to many extra-intestinal disorders. Gut commensal microbiota, in particular, plays an active role in human immune and intestinal homeostasis. Complex interactions of the microbiota with host genetics and other underlying factors lead to intestinal dysbiosis, which is thought to be linked to ocular inflammatory diseases. Thus, the aim of this review is to analyze the role of intestinal microbiome in age-related macular degeneration (AMD). Methods: A thorough literature search was performed using PubMed/MEDLINE, limited to English language publications, from January 2004 to March 2020. An additional search was made employing Google Scholar to complete the collected data as per the above-mentioned time-line and language limitations. The main keywords used included age-related macular degeneration, microbiome, dysbiosis, autoimmunity, gut microbiota, epigenetics, immune-mediated inflammatory diseases, and gut-retina axis. Results: Recent studies have proposed the role of intestinal microbiota in the pathogenesis of AMD. Changes in the microbiome have been shown to trigger several ocular inflammatory processes. There is increasing evidence demonstrating that intestinal microbial imbalance may play an important role in the pathogenesis of AMD. Conclusions: This review summarizes how alterations in the intestinal microbiota can be associated with the pathogenesis of AMD and how new therapeutic modalities can be designed to target this microbiome to limit the severe nature of this disease. Future advances in microbiome research may unveil a new era in understanding and managing AMD

Diagnostic and therapeutic approaches to optic disc pit maculopathy in children

Background: Optic disc pit (ODP) is a rare congenital defect of the optic disc that can lead to maculopathy and gradual visual impairment. This review summarizes our current knowledge on the diagnostic and therapeutic approaches to ODP maculopathy (ODP-M) in children. Methods: A thorough literature search was performed using the PubMed/MEDLINE database from 1960 to 2020. An additional search was conducted using Google Scholar for completeness. Results: ODP-M is characterized by the accumulation of subretinal and/or intraretinal fluid. The exact pathogenetic mechanisms are not fully understood, and the origin of the fluid remains unknown. Although ODP-M is more likely to occur during the third or fourth decade of life, cases of children with serous retinal detachment have been recorded. Early diagnosis of ODP-M and prompt, appropriate management are crucial, particularly in patients of amblyogenic age. In adults, ODP-M may resolve spontaneously, but most cases require surgical intervention to prevent permanent loss of vision. However, the fact that ODP-M may spontaneously resolve in children cannot be ignored. Various surgical methods have been described, including pars plana vitrectomy (PPV) combined with various techniques, including laser photocoagulation, intravitreal gas injection, and macular buckling. Conclusions: PPV remains the mainstay surgical approach for ODP-M. However, ODP-M may differ between children and adults. Children constitute a unique population of patients that require a different and probably more tailor-made approach. Detailed clinical examination, combined with a thorough analysis of retinal imaging, may improve our understanding of the background and pathophysiology of the disease and eventually provide us with new insights into the management of ODP-M in the pediatric population. How to cite this article: Kalogeropoulos D, Asproudis I,  Ch’ng SW, Mitra A, Sharma A, Katsikatsos K, Asproudis C, Kalogeropoulos C. Diagnostic and therapeutic approaches to optic disc pit maculopathy in children. Med Hypothesis Discov Innov Optom.2021 Spring; 2(1): 24-35. DOI: https://doi.org/10.51329/mehdioptometry12

Contrast-enhanced ultrasound performed under urgent conditions. Indications, review of the technique, clinical examples and limitations

Contrast-enhanced ultrasound (CEUS) is an imaging technique with various indications, most of which refer to scheduled examinations. However, CEUS can also be performed under urgent conditions for the investigation of many different clinical questions. This article reviews basic physics of ultrasound contrast agents and examines the commonest urgent clinical applications of CEUS. These include, among others, abdominal solid organ trauma and infarcts, scrotal and penile pathology and blood vessel imaging. Patients can be examined with a very short time delay at their bedside, without exposure to ionising radiation or risk of anaphylactic reaction and renal failure, while contraindications are minimal. CEUS technique is described for various urgent indications and imaging examples from our department’s experience are presented. Safety matters and limitations of CEUS are also mentioned. Teaching Points Contrast-enhanced ultrasound (CEUS) can be performed urgently for various clinical applications. Abdominal indications include solid organ trauma and infarcts. CEUS in abdominal organ trauma correlates well with CT and can replace it for patient follow-up. CEUS images testicular torsion, infection and infarction, as well as testicular and penile trauma. Blood vessels can be assessed with CEUS for obstruction, aneurysm, thrombosis and dissection

Bartonella and intraocular inflammation: a series of cases and review of literature

Chris Kalogeropoulos1, Ioannis Koumpoulis1, Andreas Mentis2, Chrisavgi Pappa1, Paraskevas Zafeiropoulos1, Miltiadis Aspiotis11Department of Ophthalmology, Medical School, University of Ioannina, Greece; 2Laboratory of Medical Microbiology, Hellenic Pasteur Institute, Athens, GreecePurpose: To present various forms of uveitis and/or retinal vasculitis attributed to Bartonella infection and review the impact of this microorganism in patients with uveitis.Methods: Retrospective case series study. Review of clinical records of patients diagnosed with Bartonella henselae and Bartonella quintana intraocular inflammation from 2001 to 2010 in the Ocular Inflammation Department of the University Eye Clinic, Ioannina, Greece. Presentation of epidemiological and clinical data concerning Bartonella infection was provided by the international literature.Results: Eight patients with the diagnosis of Bartonella henselae and two patients with B. quintana intraocular inflammation were identified. Since four patients experienced bilateral involvement, the affected eyes totaled 14. The mean age was 36.6 years (range 12–62). Uveitic clinical entities that we found included intermediate uveitis in seven eyes (50%), vitritis in two eyes (14.2%), neuroretinitis in one eye (7.1%), focal retinochoroiditis in one eye (7.1%), branch retinal vein occlusion (BRVO) due to vasculitis in one eye (7.1%), disc edema with peripapillary serous retinal detachment in one eye (7.1%), and iridocyclitis in one eye (7.1%). Most of the patients (70%) did not experience systemic symptoms preceding the intraocular inflammation. Antimicrobial treatment was efficient in all cases with the exception of the case with neuroretinitis complicated by anterior ischemic optic neuropathy and tubulointerstitial nephritis.Conclusion: Intraocular involvement caused not only by B. henselae but also by B. quintana is being diagnosed with increasing frequency. A high index of suspicion is needed because the spectrum of Bartonella intraocular inflammation is very large. In our study the most common clinical entity was intermediate uveitis.Keywords: Bartonella, neuroretinitis, intermediate uveitis, retinal vascular occlusio

Eye and Periocular Skin Involvement in Herpes Zoster Infection

Herpes zoster ophthalmicus (HZO) is a clinical manifestation of the reactivation of latent varicella zoster virus (VZV) infection and is more common in people with diminished cell-mediated immunity. Lesions and pain correspond to the affected dermatomes, mostly in first or second trigeminal branch and progress from maculae, papules to vesicles and form pustules, and crusts. Complications are cutaneous, visceral, neurological, ocular, but the most debilitating is post-herpetic neuralgia. Herpes zoster ophthalmicus may affect all the ophthalmic structures, but most severe eye-threatening complications are panuveitis, acute retinal necrosis (ARN) and progressive outer retinal necrosis (PORN) as well. Antiviral medications remain the primary therapy, mainly useful in preventing ocular involvement when begun within 72 hours after the onset of the rash. Timely diagnosis and management of HZO are critical in limiting visual morbidity. Vaccine in adults over 60 was found to be highly effective to boost waning immunity what reduces both the burden of herpes zoster (HZ) disease and the incidence of post-herpetic neuralgia (PHN)