Arrhythmogenic right ventricular dysplasia with apical thrombus atypical presentation of cardiomyopaties

Aritmojenik sağ ventrikül displazisi (ARVD) na-dir görülen bir kardiyomiyopatidir. ARVD ço-ğunlukla genç yaşlarda tanı alır ve kendisini ventriküler aritmiler, çarpıntı, baş dönmesi, kalp yetmezliği ve hatta ani kardiyak ölüm ile gösterebilir. Görüntüleme yöntemleri ile sağ ventrikül (SV) dilatasyonu ve apikal anevrizma tipik bulgusudur. Fakat ARVD olgularında int-raventriküler trombüs çok nadir görülmektedir. 19 yaşında erkek hasta, hastanemize çarpıntı ve bayılma şikâyetleri ile başvurdu. Elektrokar-diyografisinde ön yüz derivasyonlarda T nega-tifliği bulunmakta idi. Ekokardiyografide sağ ventrikül dilate ve SV apeksinde anevrizmatik oluşum içinde trombüs görüldü (Fig-1). Kardi-yak manyetik rezonans incelemede sağ vent-rikül genişlemesini, yağ infiltrasyonunu, fibro-tik dokuları, SV duvar hareket bozukluğunu ve trombüslü apikal anevrizma doğrulandı. Anti-koagulan tedaviyle üç ay sonra trombüsün rezole olduğu gözlendi ve ICD implante edildi. ARVD tanısında elektrokardiyografik, aritmik, histolojik ve ailesel özelliklerin yanında görün-tüleme yöntemleri de büyük önem taşımak-tadır. Sağ ventrikül dilatasyonu ve apikal anev-rizması tanı sürecinde önemli kriterler olmakla birlikte bu gibi bulgular saptandığında trom-büs varlığı da dikkatlice değerlendirilmelidArrhythmogenic right ventricular dysplasia (ARVD) is a rare form of cardiomyopathy. It commonly presents in young adults with ventricular tachycardia or sudden death. Right ventricular (RV) dilatation and apical aneurysm are the typical findings in imaging methods. However intraventricular thrombus is rarely seen in ARVD cases. A 19 year old male was admitted to hospital with palpitation and syncope. T wave inversion was detected on anterior surface electrocardiogram. Transthoracic echocardiography revealed dilated RV and apical aneurysm in which thrombus located (Fig-1). Cardiac magnetic rezonans imaging comfirmed RV enlargement, fatty infiltration, fibrosis, wall motion abnormalities and apical aneursym with thrombus. Anticoagulation theraphy commenced to the patient. After three months later trombus resoluted and ICD was implanted. Imaging methods have a great importance in the diagnosis of ARVD besides electrocardiographic, arrhythmic, histological and familial characteristics. While right ventricular dilatation and apical aneurysm are important criteria for the diagnosis process, the presence of thrombus should be evaluated carefully

Investigation of trap states in AlInN/AlN/GaN heterostructures by frequency-dependent admittance analysis

We present a systematic study on the admittance characterization of surface trap states in unpassivated and SiN x -passivated Al 0.83In 0.17N/AlN/GaN heterostructures. C-V and G/ω-V measurements were carried out in the frequency range of 1 kHz to 1 MHz, and an equivalent circuit model was used to analyze the experimental data. A detailed analysis of the frequency-dependent capacitance and conductance data was performed, assuming models in which traps are located at the metal-AlInN surface. The density (D t) and time constant (τ t) of the surface trap states have been determined as a function of energy separation from the conduction-band edge (E c - E t). The D st and τ st values of the surface trap states for the unpassivated samples were found to be D st≅ (4 - 13)× 10 12 eV - 1 cm - 2 and τ st ≈ 3 μs to 7 μs, respectively. For the passivated sample, D st decreased to 1.5× 10 12eV - 1cm - 2 and τ st to 1.8 μs to 2 μs. The density of surface trap states in Al 0.83In 0.17N/AlN/GaN heterostructures decreased by approximately one order of magnitude with SiN x passivation, indicating that the SiN x insulator layer between the metal contact and the surface of the Al 0.83In 0.17N layer can passivate surface states. © 2010 TMS

The effect of insulator layer thickness on the main electrical parameters in (Ni/Au)/AlxGa1-xN/AIN/GaN heterostructures

(Ni/Au)Alx Ga1-x N/AlN/GaN(x = 0.22) heterostructures with and without a passivation layer of the SiNx were fabricated in order to see the effect of the insulator layer on the main electrical parameters such as zero-bias barrier height (BH) (φBO), ideality factor (n), series resistance (Rs) of the structure, and the interface state density (Nss). Some of these parameters were determined from both I-V and admittance (C-V and G/ω-V) measurements at room temperature and at 1 MHz and were compared. The experimental results show that the value of N ss in a Schottky contact without passivation is nearly 1 order of magnitude larger than that in a Schottky contact with SiNx passivation layers. Also, the values of Rs increase with the increasing thickness of the passivation layer. In the forward bias region, the negative values of capacitance are an attractive result of this study. This negative capacitance disappears in presence of the passivation layer. Copyright © 2010 John Wiley & Sons, Ltd

Current transport mechanisms and trap state investigations in (Ni/Au)-AlN/GaN Schottky barrier diodes

The current transport mechanisms in (Ni/Au)-AlN/GaN Schottky barrier diodes (SBDs) were investigated by the use of current-voltage characteristics in the temperature range of 80-380 K. In order to determine the true current transport mechanisms for (Ni/Au)-AlN/GaN SBDs, by taking the Js(tunnel), E 0, and Rs as adjustable fit parameters, the experimental J-V data were fitted to the analytical expressions given for the current transport mechanisms in a wide range of applied biases and at different temperatures. Fitting results show the weak temperature dependent behavior in the saturation current and the temperature independent behavior of the tunneling parameters in this temperature range. Therefore, it has been concluded that the mechanism of charge transport in (Ni/Au)-AlN/GaN SBDs, along the dislocations intersecting the space charge region, is performed by tunneling. In addition, in order to analyze the trapping effects in (Ni/Au)-AlN/GaN SBDs, the capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics were measured in the frequency range 0.7-50 kHz. A detailed analysis of the frequency-dependent capacitance and conductance data was performed, assuming the models in which traps are located at the heterojunction interface. The density (Dt) and time constants (τt) of the trap states have been determined as a function of energy separation from the conduction-band edge (Ec - Et) as Dt≅ (5-8)×10 12eV-1 cm-2andτt≅(43-102) μs, respectively. © 2010 Elsevier Ltd. All rights reserved

Electrical characterization of MS and MIS structures on AlGaN/AlN/GaN heterostructures

The forward and reverse bias I-V, C-V, and G/ω-V characteristics of (Ni/Au) Schottky barrier diodes (SBDs) on the Al 0.22Ga 0.78N/AlN/GaN high-electron-mobility-transistor (HEMTs) without and with SiN x insulator layer were measured at room temperature in order to investigate the effects of the insulator layer (SiN x) on the main electrical parameters such as the ideality factor (n), zero-bias barrier height ( B0), series resistance (R s), interface-state density (N ss). The energy density distribution profiles of the N ss were obtained from the forward bias I-V characteristics by taking into account the voltage dependence of the effective barrier height ( e) and ideality factor (n V) of devices. In addition, the N ss as a function of E c-E ss was determined from the low-high frequency capacitance methods. It was found that the values of N ss and R s in SBD HEMTs decreases with increasing insulator layer thickness. © 2010 Elsevier Ltd. All rights reserved

Recovery of dialysis patients with COVID-19 : health outcomes 3 months after diagnosis in ERACODA

Background. Coronavirus disease 2019 (COVID-19)-related short-term mortality is high in dialysis patients, but longer-term outcomes are largely unknown. We therefore assessed patient recovery in a large cohort of dialysis patients 3 months after their COVID-19 diagnosis. Methods. We analyzed data on dialysis patients diagnosed with COVID-19 from 1 February 2020 to 31 March 2021 from the European Renal Association COVID-19 Database (ERACODA). The outcomes studied were patient survival, residence and functional and mental health status (estimated by their treating physician) 3 months after COVID-19 diagnosis. Complete follow-up data were available for 854 surviving patients. Patient characteristics associated with recovery were analyzed using logistic regression. Results. In 2449 hemodialysis patients (mean ± SD age 67.5 ± 14.4 years, 62% male), survival probabilities at 3 months after COVID-19 diagnosis were 90% for nonhospitalized patients (n = 1087), 73% for patients admitted to the hospital but not to an intensive care unit (ICU) (n = 1165) and 40% for those admitted to an ICU (n = 197). Patient survival hardly decreased between 28 days and 3 months after COVID-19 diagnosis. At 3 months, 87% functioned at their pre-existent functional and 94% at their pre-existent mental level. Only few of the surviving patients were still admitted to the hospital (0.8-6.3%) or a nursing home (∼5%). A higher age and frailty score at presentation and ICU admission were associated with worse functional outcome. Conclusions. Mortality between 28 days and 3 months after COVID-19 diagnosis was low and the majority of patients who survived COVID-19 recovered to their pre-existent functional and mental health level at 3 months after diagnosis

Kaygı duyarlılığı ölçeği-düzeltilmiş formunun psikometrik özellikleri ve Türk üniversite öğrencileri ve hasta grubunda içme nedenleri ve alkol kullanımı ile ilişkisi.

Anxiety Sensitivity (AS) consists of beliefs that the experience of anxiety symptoms leads to illness or additional anxiety. The aim of the present study was to examine the factor structure of the Turkish version of Anxiety Sensitivity IndexRevised (ASI-R), and to investigate associations among AS, alcohol use and drinking motives in university students and alcohol dependent inpatients. The participants were 411 university students (225 females and 186 males) and 55 (3 females and 52 males) alcohol dependent inpatients. All participants were administered ASI-R, State-Trait Anxiety Inventory-Trait Form, Beck Depression Inventory, Drinking Motives Questionnaire-Revised, and Demographic Information Form. Exploratory factor analyses revealed four lower order factors of the ASI-R: (1) fear of respiratory symptoms; (2) fear of cardiovascular symptoms; (3) fear of cognitive dyscontrol; and (4) fear of publicly observable anxiety symptoms. ANOVA revealed that the frequency and amount of alcohol use were significantly higher in male students than females. Males reported more alcohol use for Coping and Conformity Motives than did females. Regression analyses revealed that only “fear of cognitive dyscontrol” significantly predicted hazardous alcohol use of students. Coping Motives significantly predicted alcohol use after controlling the effects of demographics, depression and ASI-R lower order factors in students using alcohol. “Fear of publicly observable anxiety symptoms” significantly predicted frequency of alcohol use in students using alcohol. Students reported using alcohol mostly for Enhancement, Social, Coping, and Conformity Motives, respectively. Students with high AS reported more alcohol use for Coping, Social and Conformity Motives than those with moderate and low AS. “Fear of cognitive dyscontrol” and “fear of publicly observable anxiety symptoms” explained a significant variance of drinking motives in students. In alcohol dependent inpatients, only “fear of respiratory symptoms” had a significant correlation with Coping Motives. Patients reported having used alcohol mostly for Coping, Enhancement, Social, and Conformity Motives, respectively. Coping and Enhancement Motives were significantly correlated with alcohol use. Results were discussed within the findings in the literature.M.S. - Master of Scienc

Integrated aircraft-path assignment and robust schedule design with cruise speed control

Assignment of aircraft types, each having different seat capacity, operational expenses and availabilities, critically affects airlines’ overall cost. In this paper, we assign fleet types to paths by considering not only flight timing and passenger demand, as commonly done in the literature, but also operational expenses, such as fuel burn and carbon emission costs associated with adjusting the cruise speed to ensure the passenger connections. In response to flight time uncertainty due to the airport congestions, we allow minor adjustments on the flight departure times in addition to cruise speed control, thereby satisfying the passenger connections at a desired service level. We model the uncertainty in flight duration via a random variable arising in chance constraints to ensure the passenger connections. Nonlinear fuel and carbon emission cost functions, chance constraints and binary aircraft assignment decisions make the problem significantly more difficult. To handle them, we use mixed-integer second order cone programming. We compare the performance of a schedule generated by the proposed model to the published schedule for a major U.S. airline. On the average, there exists a 20% overall operational cost saving compared to the published schedule. To solve the large scale problems in a reasonable time, we also develop a two-stage algorithm, which decomposes the problem into planning stages such as aircraft-path assignment and robust schedule generation, and then solves them sequentially. © 2017 Elsevier Lt