Spectrum of clinicopathologic manifestations of arrhythmogenic right ventricular cardiomyopathy/dysplasia: a multicenter study

OBJECTIVES: The aim of the present investigation was to redefine the clinicopathologic profile of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC), with special reference to disease progression and left ventricular (LV) involvement. BACKGROUND: Long-term follow-up data from clinical studies indicate that ARVC is a progressive heart muscle disease that with time may lead to more diffuse right ventricular (RV) involvement and LV abnormalities and culminate in heart failure. METHODS: Forty-two patients (27 male, 15 female; 9 to 65 years old, mean [+/-SD] age 29.6 +/- 18) from six collaborative medical centers, with a pathologic diagnosis of ARVC at autopsy or heart transplantation, and with the whole heart available, were studied according to a specific clinicomorphologic protocol. RESULTS: Thirty-four patients died suddenly (16 during effort); 4 underwent heart transplantation; 2 died as a result of advanced heart failure; and 2 died of other causes. Sudden death was the first sign of disease in 12 patients; the other 30 had palpitations, with syncope in 11, heart failure in 8 and stroke in 3. Twenty-seven patients experienced ventricular arrhythmias (ventricular tachycardia in 17), and 5 received a pacemaker. Ten patients had isolated RV involvement (group A); the remaining 32 (76%) also had fibrofatty LV involvement that was observed histologically only in 15 (group B) and histologically and macroscopically in 17 (group C). Patients in group C were significantly older than those in groups A and B (39 +/- 15 years vs. 20 +/- 8.8 and 25 +/- 9.7 years, respectively), had significantly longer clinical follow-up (9.3 +/- 7.3 years vs. 1.2 +/- 2.1 and 3.4 +/- 2.2 years, respectively) and developed heart failure significantly more often (47% vs. 0 and 0, respectively). Patients in groups B and C had warning symptoms (80% and 87%, respectively, vs. 30%) and clinical ventricular arrhythmias (73% and 82%, respectively, vs. 20%) significantly more often than patients in group A. Hearts from patients in group C weighed significantly more than those from patients in groups A and B (500 +/- 150 g vs. 328 +/- 40 and 380 +/- 95 g, respectively), whereas hearts from both group B and C patients had severe RV thinning (87% and 71%, respectively, vs. 20%) and inflammatory infiltrates (73% and 88%, respectively, vs. 30%) significantly more often than those from group A patients. CONCLUSIONS: LV involvement was found in 76% of hearts with ARVC, was age dependent and was associated with clinical arrhythmic events, more severe cardiomegaly, inflammatory infiltrates and heart failure. ARVC can no longer be regarded as an isolated disease of the right ventricle.     

A miniature concentrating photovoltaic and thermal system

A novel miniature concentrating PV (MCPV) system is presented and analyzed. The system is producing both electrical and thermal energy, which is supplied to a nearby consumer. In contrast to PV/thermal (PV/T) flat collectors, the heat from an MCPV collector is not limited to low-temperature applications. The work reported here refers to the evaluation and preliminary design of the MCPV approach. The heat transport system, the electric and thermal performance, the manufacturing cost, and the resulting cost of energy in case of domestic water heating have been analyzed. The results show that the new approach has promising prospects.     

Elastic properties of β-uranium and the martensitic α′-phase in uranium-gallium alloys

Ultrasonic sound velocity measurements were used to determine the elastic constants, Young, shear, and bulk moduli of polycrystalline, β-stabilized uranium 1.6 and 2.3 at. pct gallium alloys, between 77 and 300 K. Measurements were also made, at constant heating rate from 273 to 473 K, to follow the variation of the elastic constants during the transformation from the stabilized β into the distorted orthorhombic α′-structure of uranium. The Young and shear moduli in the α′-structure are higher by about 30 pct than those in β-uranium.     

The structure of R(1-x)Ga2(1- x)(0 < x < 0.33) and its relation to RGa6 (R = Rare Earth Element) and Ga

X-ray diffraction studies were used to investigate the wide solubility range of Ga in RGa₂ type compounds observed in several systems of light rare earth metals (= R) with Ga. A model, based on pairwise substitution of R atoms by Ga atoms, is suggested to explain the observed wide solubility. Using this model it is possible to explain the change in lattice parameters of the ε phase having the formula R(_1-x)Ga₂(_1+x). The structural relationships among the phases RGa₂, R(_1-x)Ga₂(_1+x,RGa₆, and pure Ga are delineated, and the common feature of these phases which belong to widely different crystal systems is shown.     

A novel method for the determination of T-cell proliferative responses in patients with uveitis

In 1969, at the first Nursing Theory Conference, Hildegard Peplau proposed a research methodology that would guide the development of nursing knowledge. To direct nurses in the development of practice-based theory, Peplau proposed a three-step process that would assist in this pursuit. The purpose of this paper is to describe the use of Peplau's process of practice-based theory development as it has directed a program of research in the area of depression. Peplau's ideas related to practice-based theory development came at a time in nursing when grand theories were being developed and theoretical nursing was highly valued. Peplau, ahead of her time, proposed an approach that valued the development of nursing knowledge in practice, while also combining both qualitative and quantitative methods. This research methodology deserves recognition today, as one that can guide knowledge development in psychiatric nursing.     

Electron microscopy study of the early stage of the martensitic transformation in a U(Ga) alloy

Transmission electron microscopy was used to study the early stages of development of the isothermal martensitic α′ platelets within the metastableβ matrix in a U-1.6 at. pct Ga alloy. Analysis of the electron diffraction patterns allowed determination of the orientation relationship (0Ī1)_β ∥ 〈001〉_α′ and [100]_β′ oriented at 12 deg with respect to [010]_α. The habit plane, as determine by trace analysis, is the (411)_β plane.     

Double Correlations in HTSC

The Nambu–Gorkov generalized Hartree–Fock theory of superconductivity is further generalized to treat simultaneously two kinds of correlations: the correlations that lead to superconductivity, as well as the correlations that produce the pseudogap in the normal state. The treatment of these simultaneous double correlations is done by enlarging the dimension of the propagator and self-energy matrices, from two to four. The off-diagonal self-energies and the DOS are calculated. The results are compatible with tunneling and PES experiments.