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Search Results: 1 - 10 of 402595 matches for " Konstantinos M Lampropoulos "
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Apical ballooning syndrome: a case report
Konstantinos M Lampropoulos, Dimitrios Kotsas, Themistoklis A Iliopoulos
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-698
Abstract: This is a case of a 40-year-old Caucasian male without any health related problems that was submitted to an urgent coronary angiography because of acute chest pain and marked precordial T-wave inversions suggestive of acute myocardial ischemia. Coronary angiography showed no significant stenosis of the coronary arteries. Left ventriculography showed systolic apical ballooning with mild basal hypercontraction.Physicians should be aware of the presentation of apical ballooning syndrome, and the chest pain after following acute stress should not be readily attributed to anxiety.Apical ballooning syndrome, also known as Takotsubo cardiomyopathy, apical ballooning cardiomyopathy, stress-induced cardiomyopathy, Gebrochenes-Herz-Syndrom, or simply stress cardiomyopathy, is a type of non-ischemic cardiomyopathy in which there is a sudden temporary weakening of the myocardium. As this weakening can be triggered by emotional stress, such as the death of a loved one, a break-up, or constant anxiety, the condition is also known as the broken heart syndrome. Stress cardiomyopathy is a well-recognized cause of acute heart failure, lethal ventricular arrhythmias, and ventricular rupture [1]. It mimics acute coronary syndromes and is characterized by reversible left ventricular apical ballooning in the absence of angiographically significant coronary artery stenosis. Studies report that 1.7-2.2% of patients originally treated as suspected acute coronary event, were subsequently diagnosed with apical ballooning syndrome. In Japanese, “tako-tsubo” means “fishing pot for trapping octopus,” and the left ventricle of a patient diagnosed with this condition indeed resembles that shape [2]. This is a presentation of a 40-year-old Caucasian male without a pertinent medical history that was referred for an urgent coronary angiography because of acute chest pain and marked precordial T-wave inversions suggestive of acute myocardial ischemia. Coronary angiography revealed no significant steno
Early bare-metal stent thrombosis presenting with cardiogenic shock: a case report
Konstantinos M Lampropoulos, Themistoklis A Iliopoulos, Werner Budts
Journal of Medical Case Reports , 2011, DOI: 10.1186/1752-1947-5-509
Abstract: We present the case of a 64-year-old Caucasian man from Greece, with symptoms and electrocardiographic findings suggestive of acute inferior myocardial infarction, who complained of chest pain and rapidly developed cardiogenic shock 48 hours after primary percutaneous coronary intervention.The most common cause of early bare-metal stent thrombosis is stent malapposition. Intravascular ultrasound is the preferred method to recognize predictors of coronary events that are not detected by angiography.Stents have improved the safety and efficacy of percutaneous coronary interventions (PCI) by reducing acute or imminent vessel closure and by reducing restenosis rates compared with conventional balloon angioplasty [1]. In addition, coronary vasomotor reactivity has been found intact after stent implantation and long-term clinical and angiographic follow-up have attested to the durability of their action [2]. Nevertheless, coronary stent thrombosis remains a serious complication of PCI.A 64-year-old male Caucasian patient was admitted to our hospital with clinical and electrocardiographical findings suggesting acute inferior myocardial infarction. Our patient had a history of hypertension and dyslipidemia but was not taking any medication at the time of admission. Laboratory findings were suggestive of acute cardiac ischemia. His plasma levels of N-terminal pro-B-type natriuretic, troponin I, creatine kinase and creatine kinase MB isoenzyme were increased. The first transthoracic echocardiogram executed at our emergency department showed hypokinesia of the inferior and posterior left ventricular wall. Our patient received 600 mg clopidogrel, 325 mg aspirin and 5000 U of unfractionated heparin and was then transferred to the catheterization laboratory, while receiving glycoprotein IIb/IIIa inhibitors (abciximab) intravenously.Coronary angiography showed atheromatosis of his left anterior descending artery and his left circumflex artery without any evidence of severe stenose
Automatic WSDL-guided Test Case Generation for PropEr Testing of Web Services
Leonidas Lampropoulos,Konstantinos Sagonas
Electronic Proceedings in Theoretical Computer Science , 2012, DOI: 10.4204/eptcs.98.3
Abstract: With web services already being key ingredients of modern web systems, automatic and easy-to-use but at the same time powerful and expressive testing frameworks for web services are increasingly important. Our work aims at fully automatic testing of web services: ideally the user only specifies properties that the web service is expected to satisfy, in the form of input-output relations, and the system handles all the rest. In this paper we present in detail the component which lies at the heart of this system: how the WSDL specification of a web service is used to automatically create test case generators that can be fed to PropEr, a property-based testing tool, to create structurally valid random test cases for its operations and check its responses. Although the process is fully automatic, our tool optionally allows the user to easily modify its output to either add semantic information to the generators or write properties that test for more involved functionality of the web services.
Correction: Visualization of the intracavitary blood flow in systemic ventricles of Fontan patients by contrast echocardiography using particle image velocimetry
Konstantinos Lampropoulos, Werner Budts, Alexander Van de Bruaene, Els Troost, Joost P van Melle
Cardiovascular Ultrasound , 2012, DOI: 10.1186/1476-7120-10-18
Abstract: The correct legend for Figure 1 is:Sequence analysis of systemic ventricular flow during systole and diastole in Fontan patients. The vortex from the Fontan group was consistently shorter, wider and rounder. The vortices were located at the centre of the left ventricle throughout diastole and systole and did not redirect flow in a coherent, sequential fashion as in controls. The location, shape and sphericity of the main vortices differ clearly from controls in all cardiac cycle [early diastole(A), late diastole(B), ejection (C)].The correct legend for Figure 2 is:Sequence analysis of systemic ventricular flow during systole and diastole in controls. The vortex from the control group was compact, elliptically shaped, and located apically. The location, shape and sphericity of the main vortices differ clearly from the Fontan group in all cardiac cycle [early diastole(A), late diastole(B), ejection (C)].It was also noted the legends for the Additional file 1 and Addition file 2 were also incorrect:The correct legend for Additional file 1 is:The flow patterns of a 38 year old female without cardiac abnormalitiesThe correct legend for Additional file 2 is:The flow pattern of a 29 year old male with Fontan circulation.The authors would like to apologize for any inconvenience caused by this error.
Visualization of the intracavitary blood flow in systemic ventricles of Fontan patients by contrast echocardiography using particle image velocimetry
Konstantinos Lampropoulos, Werner Budts, Alexander Van de Bruaene, Els Troost, Joost P van Melle
Cardiovascular Ultrasound , 2012, DOI: 10.1186/1476-7120-10-5
Abstract: Twenty-three patients (8 Fontan and 15 normal patients) underwent echocardiography with intravenous contrast agent (Sonovue?) administration. Dedicated software was used to perform particle image velocimetry (PIV) and to visualize intracavitary flow in the systemic ventricles of the patients. Vortex parameters including vortex depth, length, width, and sphericity index were measured. Vortex pulsatility parameters including relative strength, vortex relative strength, and vortex pulsation correlation were also measured.The data from this study show that it is feasible to perform particle velocimetry in Fontan patients. Vortex length (VL) was significantly lower (0.51 ± 0.09 vs 0.65 ± 0.12, P = 0.010) and vortex width (VW) (0.32 ± 0.06 vs 0.27 ± 0.04, p = 0.014), vortex pulsation correlation (VPC) (0.26 ± 0.25 vs -0.22 ± 0.87, p = 0.05) were significantly higher in Fontan patients. Sphericity index (SI) (1.66 ± 0.48 vs 2.42 ± 0.62, p = 0.005), relative strength (RS) (0.77 ± 0.33 vs 1.90 ± 0.47, p = 0.0001), vortex relative strength (VRS) (0.18 ± 0.13 vs 0.43 ± 0.14, p = 0.0001) were significantly lower in the Fontan patients group.PIV using contrast echocardiography is feasible in Fontan patients. Fontan patients had aberrant flow patterns as compared to normal hearts in terms of position, shape and sphericity of the main vortices. The vortex from the Fontan group was consistently shorter, wider and rounder than in controls. Whether vortex characteristics are related with clinical outcome is subject to further investigation.Particle image velocimetry is a new technique of determining the velocity and the direction of fluid streams by analyzing the change in position of small particles that drift with the fluid. With the recent development of echocardiographic technology, it is now possible to apply this approach to contrast-enhanced echocardiographic imaging [1-3].The growing knowledge about the structure and function of the ventricle [4] was of high interest to us in
Organochlorine Pesticides Residues in Mussels of Greek Island Evia
Konstantinos M. Kasiotis
International Journal of Chemistry , 2009, DOI: 10.5539/ijc.v1n2p3
Abstract: A simple and effective analytical procedure was developed for the determination of some organochlorine residues in mussel samples of two sampling points in Evia Island, Greece. The sample extraction was performed on lyophilized samples using either the Microwave Assisted Solvent Extraction (MASE) or the Soxhlet extraction technique. Using both techniques aldrin, endrin and endosulfan sulfate were determined. The quantification of these pesticides was carried out by Gas Chromatography-Mass Spectrometry (GC-MS) working in the Selected Ion Monitoring (SIM) mode and the recoveries ranged from 75 to 102% at two spiking levels for 6 replicates.
Enhanced Uplink Scheduling for Continuous Connectivity in High Speed Packet Access Systems  [PDF]
Saied M. Abd El-Atty, Konstantinos Lizos
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2012, DOI: 10.4236/ijcns.2012.58055
Abstract: The efficiency of high speed packet access (HSPA) systems is mainly based on channel quality information (CQI) reports transmitted by user equipment (UE) to Node B. In this paper, we propose an improved CQI prediction scheme based on a finite state Markov chain (FSMC) model for wireless channel, in order to reduce CQI signaling overhead in the HSPA system. Then, we introduce an enhanced uplink packet scheduling (EUPS) scheme to provide quality of services (QoS) guaranteed for continuous packet connectivity in the enhanced uplink (EUL). EUPS serves the active UEs not only according to buffer status but also according to reported state of the wireless channel of each UE. The performance of the proposed scheme in terms of average packet delay, average packet drop and average cell throughput is compared to the classical scheduler of 3GPP standards. The simulation results show the effectiveness of the proposed scheme.
Radio Access Selection in Integrated UMTS/WLAN Networks  [PDF]
I. MODEAS, A. KALOXYLOS, G. LAMPROPOULOS, N. PASSAS, L. MERAKOS
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2009, DOI: 10.4236/ijcns.2009.29094
Abstract: Heterogeneous networks combine different access technologies. An important problem in such networks is the selection of the most suitable radio access network. To perform this task efficiently, a lot of information is required, such as signal strength, QoS, monetary cost, battery consumption, and user preferences. These are well known issues and a considerable effort has been made to tackle them using a number of solutions. These efforts improve the performance of vertical handover but also add considerable complexity. In this paper, we introduce an enhanced algorithm for radio access network selection, which is simple, flexible and applicable to future mobile systems. Its main characteristics are the distribution of the radio access selection process among the mobile terminal and the core network, the evaluation of mobile terminal connections separately and the primary role of user preferences in the final decision. The performance of the algorithm is evaluated through simulation results, which show that the algorithm provides a high rate of user satisfaction. It decreases the messages required for the vertical handovers in the whole network and it alleviates the core network from the processing of unnecessary requests.
Realization of random-field dipolar Ising ferromagnetism in a molecular magnet
Bo Wen,P. Subedi,Lin Bo,Y. Yeshurun,M. P. Sarachik,A. D. Kent,C. Lampropoulos,G. Christou
Physics , 2009, DOI: 10.1103/PhysRevB.82.014406
Abstract: The longitudinal magnetic susceptibility of single crystals of the molecular magnet Mn$_{12}$-acetate obeys a Curie-Weiss law, indicating a transition to a ferromagnetic phase due to dipolar interactions. With increasing magnetic field applied transverse to the easy axis, the transition temperature decreases considerably more rapidly than predicted by mean field theory to a T=0 quantum critical point. Our results are consistent with an effective Hamiltonian for a random-field Ising ferromagnet in a transverse field, where the randomness is induced by an external field applied to Mn$_{12}$-acetate crystals that are known to have an intrinsic distribution of locally tilted magnetic easy axes.
Particle Production of Vector Fields: Scale Invariance is Attractive
Konstantinos Dimopoulos,Jacques M. Wagstaff
Physics , 2010, DOI: 10.1103/PhysRevD.83.023523
Abstract: In a model of an Abelian vector boson with a Maxwell kinetic term and non-negative mass-squared it is demonstrated that, under fairly general conditions during inflation, a scale-invariant spectrum of perturbations for the components of a vector field, massive or not, whose kinetic function (and mass) is modulated by the inflaton field is an attractor solution. If the field is massless, or if it remains light until the end of inflation, this attractor solution also generates anisotropic stress, which can render inflation weakly anisotropic. The above two characteristics of the attractor solution can source (independently or combined together) significant statistical anisotropy in the curvature perturbation, which may well be observable in the near future.
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